--- name: "bgpd.conf" section: "5" platform: "linux" package: "openbgpd" version: "8.8-1" release: "Debian 13 (Trixie)" platforms: ["linux", "openbsd"] url: "https://new.carta.tech/bgpd.conf" --- # bgpd.conf(5) BGP routing daemon configuration file ## NAME **bgpd.conf** – BGP routing daemon configuration file ## DESCRIPTION The [bgpd(8)](/bgpd/8.md) daemon implements the Border Gateway Protocol version 4 as described in RFC 4271. The **bgpd.conf** config file is divided into the following main sections: - MACROS User-defined variables may be defined and used later, simplifying the configuration file. - GLOBAL CONFIGURATION Global settings for [bgpd(8)](/bgpd/8.md). - SET CONFIGURATION Various lookup tables are defined in this section. - NETWORK AND FLOWSPEC ANNOUNCEMENTS Networks which should be announced by [bgpd(8)](/bgpd/8.md) are set in this section. - MPLS VPN CONFIGURATION The definition and properties for BGP MPLS VPNs are set in this section. - NEIGHBORS AND GROUPS [bgpd(8)](/bgpd/8.md) establishes sessions with *neighbors*. The neighbor definition and properties are set in this section, as well as grouping neighbors for the ease of configuration. - FILTER Filter rules for incoming and outgoing *UPDATES*. With the exception of macros, the sections should be grouped and appear in **bgpd.conf** in the order shown above. The current line can be extended over multiple lines using a backslash (‘\\’). Comments can be put anywhere in the file using a hash mark (‘#’), and extend to the end of the current line. Care should be taken when commenting out multi-line text: the comment is effective until the end of the entire block. Argument names not beginning with a letter, digit, or underscore must be quoted. Additional configuration files can be included with the **include** keyword, for example: ``` include "/etc/bgpd/bgpd-10.0.0.1.filter" ``` ## MACROS Macros can be defined that will later be expanded in context. Macro names must start with a letter, digit, or underscore, and may contain any of those characters. Macro names may not be reserved words (for example, **AS**, **neighbor**, or **group**). Macros are not expanded inside quotes. For example: ``` peer1="1.2.3.4" neighbor $peer1 { remote-as 65001 } ``` ## GLOBAL CONFIGURATION These settings affect the operation of the [bgpd(8)](/bgpd/8.md) daemon as a whole. - **AS** *as-number* \[*as-number*\] Set the local *autonomous* *system* number to *as-number*. A fallback 2-byte AS number may follow a 4-byte AS number for neighbors that do not support 4-byte AS numbers. The standard and default fallback AS number is 23456. The AS numbers are assigned by local RIRs, such as: - AfriNIC for Africa - APNIC for Asia Pacific - ARIN for North America and parts of the Caribbean - LACNIC for Latin America and the Caribbean - RIPE NCC for Europe, the Middle East, and parts of Asia The AS numbers 64512 – 65534 are designated for private use. The AS number 23456 is reserved and should not be used. 4-byte AS numbers may be specified in either the ASPLAIN format: ``` AS 196618 ``` or in the older ASDOT format: ``` AS 3.10 ``` - **connect-retry** *seconds* Set the number of seconds to wait before attempting to re-open a connection. This timer should be sufficiently large in EBGP configurations. The default is 120 seconds. - **dump** \[**rib** *name*\] (**table-v2**\|**table-mp**\|**table**) *file* \[*interval*\] - **dump** (**all**\|**updates**) (**in**\|**out**) *file* \[*interval*\] Dump the RIB, a.k.a. the *routing* *information* *base*, or dump ongoing BGP activity, in Multi-threaded Routing Toolkit (MRT) format. The *file* is subject to [strftime(3)](/strftime/3.md)-expansion. The **table-v2** and **table-mp** RIB formats store multi-protocol RIBs correctly, but the **table** format does not. The latter two are provided only to support third-party tools lacking support for the recommended **table-v2** format. Dump an alternative RIB by specifying *name*. Specify an *interval* in seconds for periodic RIB dumps. The following will dump the entire RIB table, at startup and every 5 minutes thereafter, to a new file: ``` dump table-v2 "/tmp/rib-dump-%H%M" 300 ``` Dumps of ongoing BGP activity include all BGP state transitions, and all BGP messages in the specified direction. Use **updates** to dump only BGP *UPDATE* messages, without state transitions. Specify an *interval* in seconds to restart periodically with a new file: ``` dump all in "/tmp/all-in-%H%M" 300 ``` - **fib-priority** *prio* Set the routing priority to *prio*. The default is 48. - **fib-update** (**yes**\|**no**) If set to **no**, do not update the Forwarding Information Base, a.k.a. the kernel routing table. The default is **yes**. - **holdtime** *seconds* Set the announced holdtime in seconds. This is exchanged with a neighbor upon connection establishment, in the *OPEN* message, and the shortest holdtime governs the session. The neighbor session is dropped if the session holdtime passes without receipt of a *KEEPALIVE* or an *UPDATE* message from the neighbor. The default is 90 seconds. - **holdtime** **min** *seconds* The minimum acceptable holdtime in seconds. This value must be at least 3. - **listen** **on** *address* \[**port** *port*\] Specify the local IP address and optional port for [bgpd(8)](/bgpd/8.md) to listen on. The default is to listen on all local addresses on the current default routing domain. - **log** **updates** Log sent and received BGP update messages. - **nexthop** **qualify** **via** (**bgp**\|**default**) If set to **bgp**, [bgpd(8)](/bgpd/8.md) may verify nexthops using BGP routes. If set to **default**, [bgpd(8)](/bgpd/8.md) may verify nexthops using the default route. By default [bgpd(8)](/bgpd/8.md) uses only static routes or routes added by other routing daemons, such as [ospfd(8)](/ospfd/8.md). - **rde** **evaluate** (**default**\|**all**) If set to *all*, keep evaluating alternative paths in case the selected path is filtered out. By default if a path is filtered by the output filters then no alternative path is sent to this peer. - **rde** **med** **compare** (**always**\|**strict**) If set to **always**, the *MULTI\_EXIT\_DISC* attributes will always be compared. The default is **strict**, where the metric is only compared between peers belonging to the same AS. - **rde** **rib** *name* \[**no** **evaluate**\] - **rde** **rib** *name* \[**rtable** *number*\] Create an additional RIB named *name*. The degree to which its routes may be utilized is configurable. They may be excluded from the decision process that selects usable routes with the **no** **evaluate** flag, and this precludes their export to any kernel routing table. By default its routes will be evaluated, but not exported to the kernel. They may be both evaluated and exported if associated with a given **rtable** *number*, which must belong to the routing domain that [bgpd(8)](/bgpd/8.md) was started in. This table will not be consulted during nexthop verification unless it is the one that [bgpd(8)](/bgpd/8.md) was started in. It is unnecessary to create **Adj-RIB-In** and **Loc-RIB**, which are created automatically and used by default. - **rde** **rib** **Loc-RIB** **include** **filtered** Include filtered prefixes in the **Loc-RIB**. Filtered prefixes are not eligible by the decision process but can be displayed by [bgpctl(8)](/bgpctl/8.md). - **rde** **route-age** (**ignore**\|**evaluate**) If set to **evaluate**, the route decision process will also consider the age of the route in addition to its path attributes, giving preference to the older, typically more stable, route. This renders the decision process nondeterministic. The default is **ignore**. - **reject** **as-set** (**yes**\|**no**) If set to **yes**, *AS* *paths* attributes containing *AS\_SET* path segments will be rejected and all prefixes will be treated as withdraws. The default is **yes**. - **router-id** *dotted-quad* Set the BGP router ID, which must be non-zero and should be unique within the AS. By default, the router ID is the highest IPv4 address assigned to the local machine. ``` router-id 10.0.0.1 ``` - **rtable** *number* Work with the given kernel routing table instead of the default table, which is the one [bgpd(8)](/bgpd/8.md) was started in. For nexthop verification, [bgpd(8)](/bgpd/8.md) will always consult the default table. This is the same as using the following syntax: ``` rde rib Loc-RIB rtable number ``` - **socket** "*path*" \[**restricted**\] Create a control socket at *path*. If **restricted** is specified, a restricted control socket will be created. By default */run/openbgpd/bgpd.sock.\* is used where *\* is the routing domain in which [bgpd(8)](/bgpd/8.md) has been started. By default, no restricted socket is created. - **staletime** *seconds* Set the upper bound in seconds stale routes are kept during graceful restart. The default is 180 seconds. - **transparent-as** (**yes**\|**no**) If set to **yes**, attribute transparency is enabled. *AS* *paths* to EBGP neighbors are not prepended with the local AS. Additionally, the MULTI\_EXIT\_DISC attribute is passed transparently and automatic filtering based on the well-known communities **NO\_EXPORT**, **NO\_ADVERTISE**, and **NO\_EXPORT\_SUBCONFED** is disabled. The default is **no**. ## SET CONFIGURATION [bgpd(8)](/bgpd/8.md) supports the efficient lookup of data within named *sets*. An **as-set**, a **prefix-set**, and an **origin-set** store AS numbers, prefixes, and prefixes/source-as pairs, respectively. Such sets may be referenced by filter rules; see the FILTER section for details. It is more efficient to evaluate a set than a long series of rules for filtering each of its members. One single **roa-set** may be defined, against which [bgpd(8)](/bgpd/8.md) will validate the origin of each prefix. The **roa-set** and the **aspa-set** are merged with the corresponding tables received via **rtr** sessions. A set definition can span multiple lines, and an optional comma is allowed between elements. The same set can be defined more than once, in this case the definitions are merged into one common set. - **as-set** *name* **{** *as-number* *...* **}** An **as-set** stores AS numbers, and can be used with the AS specific parameter in FILTER rules. - **aspa-set** **{** **customer-as** *as-number* \[**expires** *seconds*\] **provider-as** **{** *as-number* **...** **}** **...** **}** The **aspa-set** holds a collection of *Validated* *ASPA* *Payloads* (VAPs). Each as AS\_PATH received from an eBGP peer is checked against the **aspa-set**, and the ASPA Validation State (AVS) is set. **expires** can be set to the seconds since Epoch until when this VAP is valid. ``` aspa-set { customer-as 64511 provider-as { 64496 65496 } customer-as 64496 provider-as { 65496 64544 } } ``` - **origin-set** *name* **{** *address*/*len* \[**maxlen** *mlen*\] **source-as** *asn* *...* **}** An **origin-set** stores prefix/source-as pairs, and can be used to filter on the combination by using the **origin-set** parameter in FILTER rules. ``` origin-set private { 10.0.0.0/8 maxlen 24 source-as 64511 203.0.113.0/24 source-as 64496 } ``` - **prefix-set** *name* **{** *address*/*len* *...* **}** A **prefix-set** stores network prefixes and can be used in place of the **prefix** parameter in FILTER rules, and in **network** statements. A prefix can be followed by the prefixlen operators listed for the **prefix** parameter in the PARAMETERS section. The first example below creates a set of prefixes called “private”, to hold a number of RFC 1918 private network blocks. The second example shows the use of prefixlen operators. ``` prefix-set private { 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, fc00::/7 } prefix-set as64496set { 192.0.2.0/24 prefixlen >= 26, 2001:db8::/32 or-longer } ``` - **roa-set** **{** *address*/*len* \[**maxlen** *mlen*\] **source-as** *asn* \[**expires** *seconds*\] ... **}** The **roa-set** holds a collection of *Validated* *ROA* *Payloads* (VRPs). Each received prefix is checked against the **roa-set**, and the Origin Validation State (OVS) is set. **expires** can be set to the seconds since Epoch until when this VRP is valid. ``` roa-set { 192.0.2.0/23 maxlen 24 source-as 64511 203.0.113.0/24 source-as 64496 } ``` - **rtr** *address* **{** *...* **}** The **rtr** block specifies a *RPKI* *to* *Router* (RTR) session. *RTR* sessions provide another means to load *VRP* sets into [bgpd(8)](/bgpd/8.md). Changes propagated via the RTR protocol do not need a config reload and are immediately applied. The union of all *VRP* sets received via **rtr** sessions and the entries in the **roa-set** is used to validate the origin of routes. The rtr session properties are as follows: - **descr** *description* Add a description. The description is used in logging and status reports, but has no further meaning for [bgpd(8)](/bgpd/8.md). - **local-address** *address* Bind to the specific IP address before opening the TCP connection to the *rtr* server. **min-version** *number* Require a minimal RTR version of *number*. To ensure that ASPA records are synchronised over RTR a minimal version of 2 is required. - **port** *number* Specify the TCP destination port for the *rtr* session. If not specified, the default **port** is *323*. ## NETWORK AND FLOWSPEC ANNOUNCEMENTS **network** statements specify the networks that [bgpd(8)](/bgpd/8.md) will announce as its own. An announcement must also be permitted by the FILTER rules. By default [bgpd(8)](/bgpd/8.md) announces no networks. - **network** *address*/*prefix* \[**set** **...**\] Announce the specified prefix as belonging to our AS. - **network** (**inet**\|**inet6**) **connected** \[**set** **...**\] Announce routes to directly attached networks. - **network** **prefix-set** *name* \[**set** **...**\] Announce all networks in the prefix-set *name*. - **network** (**inet**\|**inet6**) **priority** *number* \[**set** **...**\] Announce routes having the specified *priority*. - **network** (**inet**\|**inet6**) **rtlabel** *label* \[**set** **...**\] Announce routes having the specified *label*. - **network** (**inet**\|**inet6**) **static** \[**set** **...**\] Announce all static routes. Each **network** statement may set default *AS* *path* *attributes*: ``` network 192.168.7.0/24 set localpref 220 ``` See also the ATTRIBUTE SET section. **flowspec** statements specify the flowspec rules that [bgpd(8)](/bgpd/8.md) will announce as its own. By default [bgpd(8)](/bgpd/8.md) announces no flowspec rules. - **flowspec** (**inet**\|**inet6**) *rule* \[**set** **...**\] Announce an IPv4 or IPv6 specific flowspec *rule* including the *AS* *path* *attributes* specified by *set*. The following rule parameters can be set. Most number arguments in the below rules can be specified as a list of ranges enclosed in curly brackets using these operators: ``` = (equal, default) != (unequal) < (less than) <= (less than or equal) > (greater than) >= (greater than or equal) - (range including boundaries) >< (except range) ``` ‘\>\<’, and ‘-’ are binary operators (they take two arguments). - **from** *source* \[**port** *list*\] - **to** *dest* \[**port** *list*\] This rule applies only to packets with the specified source or destination addresses and ports. Addresses can be specified in CIDR notation (matching netblocks) or using **any** to match any address. In most cases a **to** address must be specified and be part of the announced networks. Ports can be specified either by number or by name. For example, port 80 can be specified as **www**. For a list of all port name to number mappings see the file */etc/services*. - **flags** *a*/*b* This rule only applies to TCP packets that have the flags *a* set out of set *b*. Flags not specified in *b* are ignored. The flags are: (F)IN, (S)YN, (R)ST, (P)USH, (A)CK, (U)RG, (E)CE, and C(W)R. - **fragment** *a*/*b* This rule only applies to fragmented packets which match the specified flags. The flags are: (D)on't fragment, (I)s fragment, (F)irst fragment, and (L)ast fragment. - **icmp-type** *type* \[**code** *code*\] - **icmp6-type** *type* \[**code** *code*\] This rule only applies to ICMP or ICMP6 packets with the specified type and code. Text names for ICMP types and codes are listed in [icmp(4)](/icmp/4.md) and [icmp6(4)](/icmp6/4.md). - **length** *pktlen* This rule applies only to packets matching the specified *pktlen*. - **proto** *protocol* This rule applies only to packets of this protocol. Common protocols are ICMP, ICMP6, TCP, and UDP. For a list of all the protocol name to number mappings see the file */etc/protocols*. - **tos** *string*\|*number* This rule applies to packets with the specified TOS bits set. *string* may be one of **critical**, **inetcontrol**, **lowdelay**, **netcontrol**, **throughput**, **reliability**, or one of the DiffServ Code Points: **ef**, **af11** ... **af43**, **cs0** ... **cs7**; *number* may be either a hex or decimal number. The action taken when a flowspec rules matches depends on extended communities. For example to block all traffic either **ext-community** **flow-rate** *as-number*:0 or **ext-community** **flow-pps** *as-number*:0 need to be set. ## MPLS VPN CONFIGURATION A **vpn** section configures a router to participate in an MPLS Virtual Private Network. It specifies an [mpe(4)](/mpe/4.md) interface to use, a description, and various properties of the VPN: ``` vpn "description" on mpe1 { rd 65002:1 import-target rt 65002:42 export-target rt 65002:42 network 192.168.1/24 } ``` [bgpd(8)](/bgpd/8.md) will not exchange VPN routes with a neighbor by default, see the NEIGHBORS AND GROUPS section. The description is used when logging but has no further meaning to [bgpd(8)](/bgpd/8.md). The [mpe(4)](/mpe/4.md) interface will be used as the outgoing interface for routes to the VPN, and local networks will be announced with the MPLS label specified on the interface. The interface can provide VPN connectivity for another rdomain by being configured in that rdomain. The required rdomain must be configured on the interface before [bgpd(8)](/bgpd/8.md) uses it. Multiple VPNs may be connected to a single rdomain, including the rdomain that [bgpd(8)](/bgpd/8.md) is running in. An example [hostname.if(5)](/hostname.if/5.md) configuration for an [mpe(4)](/mpe/4.md) interface providing connectivity to rdomain 1: ``` rdomain 1 mplslabel 2000 inet 192.198.0.1 255.255.255.255 up ``` The VPN properties are as follows: - **export-target** *subtype* *as-number*:*local* - **export-target** *subtype* *IP*:*local* Classify announced networks by tagging them with an *extended* *community* of the given arguments. The community *subtype* should be a *route* *target*, **rt**, to ensure interoperability. The arguments are further detailed in the ATTRIBUTE SET section. More than one **export-target** can be specified. - **fib-update** (**yes**\|**no**) If set to **no**, do not update the Forwarding Information Base, a.k.a. the kernel routing table. The default is **yes**. - **import-target** *subtype* *as-number*:*local* - **import-target** *subtype* *IP*:*local* The rdomain imports only those prefixes tagged with an *extended* *community* matching an **import-target**. The community *subtype* should be a *route* *target*, **rt**, to ensure interoperability. The arguments are further detailed in the ATTRIBUTE SET section. More than one **import-target** can be specified. - **network** *argument* *...* Announce the given networks within this VPN; see the NETWORK ANNOUNCEMENTS section. - **rd** *as-number*:*local* - **rd** *IP*:*local* The Route Distinguisher **rd** supplies BGP with namespaces to disambiguate VPN prefixes, as these needn't be globally unique. Unlike route targets, the **rd** neither identifies the origin of the prefix nor controls into which VPNs the prefix is distributed. The *as-number* or *IP* of a **rd** should be set to a number or IP that was assigned by an appropriate authority, whereas *local* can be chosen by the local operator. ## NEIGHBORS AND GROUPS [bgpd(8)](/bgpd/8.md) establishes TCP connections to other BGP speakers called *neighbors*. A neighbor and its properties are specified by a **neighbor** section: ``` neighbor 10.0.0.2 { remote-as 65002 descr "a neighbor" } ``` Neighbors placed within a **group** section inherit the properties common to that group: ``` group "peering AS65002" { remote-as 65002 neighbor 10.0.0.2 { descr "AS65002-p1" } neighbor 10.0.0.3 { descr "AS65002-p2" } } ``` An entire network of neighbors may be accommodated by specifying an address/netmask pair: ``` neighbor 10.0.0.0/8 ``` This is a *template* that recognises as a neighbor any connection from within the given network. Such neighbors inherit their template's properties, except for their IP address. A template may omit **remote-as**; [bgpd(8)](/bgpd/8.md) then accepts any AS presented by the neighbor in the *OPEN* message. The neighbor properties are as follows: - **announce** (**IPv4**\|**IPv6**) (**none**\|**unicast**\|**vpn**\|**flowspec**) \[**enforce**\] For the given address family, control which *subsequent* *address* *families* are announced during the capabilities negotiation. Only routes for that address family and subsequent address families will be announced and processed. At the moment, only **none**, which disables the announcement of that address family, **unicast**, **vpn**, which allows the distribution of BGP MPLS VPNs, and **flowspec**, which allows the distribution of Flow Specification Rules, are supported. The default is **unicast** for the same address family of the session. - **announce** **add-path** **recv** (**yes**\|**no**\|**enforce**) If set to **yes**, the receive add-path capability is announced, which allows reception of multiple paths per prefix. The default is **no**. - **announce** **add-path** **send** (**no**\|**all**) \[**enforce**\] - **announce** **add-path** **send** (**best**\|**ecmp**\|**as-wide-best**) \[**plus** *num*\] \[**max** *num*\] \[**enforce**\] If set to **all**, **best**, **ecmp**, or **as-wide-best**, the send add-path capability is announced, which allows sending multiple paths per prefix. The paths sent depend on which mode is selected: - **no** do not advertise add-path send capability - **all** send all valid paths - **best** send the best path - **ecmp** send paths with equal nexthop cost - **as-wide-best** send paths where the first 8 checks of the decision process match **plus** allows the inclusion of additional backup paths and works for **best**, **ecmp**, and **as-wide-best**. **max** can be used to limit the total amount of paths sent for **ecmp** and **as-wide-best**. Right now **ecmp** and **as-wide-best** are equivalent. The default is **no**. If **add-path** **send** is active then the setting of **rde** **evaluate** is ignored. - **announce** **as-4byte** (**yes**\|**no**\|**enforce**) If set to **no**, the 4-byte AS capability is not announced and so native 4-byte AS support is disabled. If **enforce** is set, the session will only be established if the neighbor also announces the capability. The default is **yes**. - **announce** **enhanced** **refresh** (**yes**\|**no**\|**enforce**) If set to **yes**, the enhanced route refresh capability is announced. If **enforce** is set, the session will only be established if the neighbor also announces the capability. The default is **no**. - **announce** **extended** **message** (**yes**\|**no**\|**enforce**) If set to **yes**, the extended message capability is announced. If negotiated, the default maximum message size is increased from 4096 to 65535 bytes. If **enforce** is set, the session will only be established if the neighbor also announces the capability. The default is **no**. - **announce** **extended** **nexthop** (**yes**\|**no**\|**enforce**) If set to **yes**, the extended nexthop encoding capability is announced. If negotiated, **IPv4** **unicast** and **vpn** sessions can send paths with a IPv6 nexthop. If **enforce** is set, the session will only be established if the neighbor also announces the capability. The default is **no**. - **announce** **graceful** **notification** (**yes**\|**no**) If set to **yes**, the graceful notification extension to graceful restart is announced. The default is **no**. **announce** **refresh** must be enabled to enable graceful notifications. - **announce** **policy** (**yes**\|**no**\|**enforce**) If set to **yes**, add the open policy role capability. If the role of the neighbor does not correspond to the expected role then the session will be closed. If **enforce** is set, the session will only be established if the neighbor also announces the capability. The default is **no**. - **announce** **refresh** (**yes**\|**no**\|**enforce**) If set to **no**, the route refresh capability is not announced. If **enforce** is set, the session will only be established if the neighbor also announces the capability. The default is **yes**. - **announce** **restart** (**yes**\|**no**\|**enforce**) If set to **no**, the graceful restart capability is not announced. Currently only the End-of-RIB marker is supported and announced by the **restart** capability. If **enforce** is set, the session will only be established if the neighbor also announces the capability. The default is **yes**. - **as-override** (**yes**\|**no**) If set to **yes**, all occurrences of the neighbor AS in the *AS* *path* will be replaced with the local AS before running the filters. The Adj-RIB-In still holds the unmodified AS path. The default value is **no**. - **demote** *group* Increase the [carp(4)](/carp/4.md) demotion counter on the given interface group, usually *carp*, when the session is not in state *ESTABLISHED*. The demotion counter will be increased as soon as [bgpd(8)](/bgpd/8.md) starts and decreased 60 seconds after the session went to state *ESTABLISHED*. For neighbors added at runtime, the demotion counter is only increased after the session has been *ESTABLISHED* at least once before dropping. For more information on interface groups, see the **group** keyword in [ifconfig(8)](/ifconfig/8.md). - **depend** **on** *interface* The neighbor session will be kept in state *IDLE* as long as *interface* reports no link. For [carp(4)](/carp/4.md) interfaces, no link means that the interface is currently *backup*. This is primarily intended to be used with [carp(4)](/carp/4.md) to reduce failover times. The state of the network interfaces on the system can be viewed using the **show** **interfaces** command to [bgpctl(8)](/bgpctl/8.md). - **descr** *description* Add a description. The description is used when logging neighbor events, in status reports, for specifying neighbors, etc., but has no further meaning to [bgpd(8)](/bgpd/8.md). - **down** \[*reason*\] Do not start the session when [bgpd(8)](/bgpd/8.md) comes up but stay in *IDLE*. If the session is cleared at runtime, after a **down** *reason* was configured at runtime, the *reason* is sent as Administrative Shutdown Communication. The *reason* cannot exceed 255 octets. - **dump** (**all**\|**updates**) (**in**\|**out**) *file* \[*interval*\] Dump ongoing BGP activity for a particular neighbor. See also the **dump** setting in GLOBAL CONFIGURATION. - **enforce** **local-as** (**yes**\|**no**) If set to **no**, *AS* *paths* will not be checked for AS loop detection. This feature is similar to allowas-in in some other BGP implementations. Since there is no AS path loop check, this feature is dangerous, and requires you to add filters to prevent receiving your own prefixes. The default value is **yes**. - **enforce** **neighbor-as** (**yes**\|**no**) If set to **yes**, *AS* *paths* whose *leftmost* *AS* is not equal to the *remote* *AS* of the neighbor are rejected and a *NOTIFICATION* is sent back. The default value for IBGP peers is **no** otherwise the default is **yes**. - **export** (**none**\|**default-route**) If set to **none**, no *UPDATE* messages will be sent to the neighbor. If set to **default-route**, only the default route will be announced to the neighbor. - **holdtime** *seconds* Set the holdtime in seconds. Inherited from the global configuration if not given. - **holdtime** **min** *seconds* Set the minimal acceptable holdtime. Inherited from the global configuration if not given. - **ipsec** (**ah**\|**esp**) (**in**\|**out**) **spi** *spi-number* *authspec* \[*encspec*\] Enable IPsec with static keying. There must be at least two **ipsec** statements per peer with manual keying, one per direction. *authspec* specifies the authentication algorithm and key. It can be ``` sha1 md5 ``` *encspec* specifies the encryption algorithm and key. **ah** does not support encryption. With **esp**, encryption is optional. *encspec* can be ``` 3des 3des-cbc aes aes-128-cbc ``` Keys must be given in hexadecimal format. After changing settings, a session needs to be reset to use the new keys. The **ipsec** flows only work with session using the default port 179. - **ipsec** (**ah**\|**esp**) **ike** Enable IPsec with dynamic keying. In this mode, [bgpd(8)](/bgpd/8.md) sets up the flows, and a key management daemon such as [isakmpd(8)](/isakmpd/8.md) is responsible for managing the session keys. With [isakmpd(8)](/isakmpd/8.md), it is sufficient to copy the peer's public key, found in */etc/isakmpd/local.pub*, to the local machine. It must be stored in a file named after the peer's IP address and must be stored in */etc/isakmpd/pubkeys/ipv4/*. The local public key must be copied to the peer in the same way. As [bgpd(8)](/bgpd/8.md) manages the flows on its own, it is sufficient to restrict [isakmpd(8)](/isakmpd/8.md) to only take care of keying by specifying the flags **-Ka**. This can be done in rc.conf.local(8). After starting the [isakmpd(8)](/isakmpd/8.md) and [bgpd(8)](/bgpd/8.md) daemons on both sides, the session should be established. After changing settings, a session needs to be reset to use the new keys. The **ipsec** flows only work with session using the default port 179. - **local-address** *address* - **no** **local-address** When [bgpd(8)](/bgpd/8.md) initiates the TCP connection to the neighbor system, it normally does not bind to a specific IP address. If a **local-address** is given, [bgpd(8)](/bgpd/8.md) binds to this address first. **no** **local-address** reverts back to the default. - **local-as** *as-number* \[*as-number*\] Set the AS number sent to the remote system. Used as described above under GLOBAL CONFIGURATION option **AS**. Since there is no AS path loop check, this option is dangerous, and requires you to add filters to prevent receiving your ASNs. Intended to be used temporarily, for migrations to another AS. - **log** **no** Disable neighbor specific logging. - **log** **updates** Log received and sent updates for this neighbor. - **max-prefix** *number* \[**restart** *number*\] Terminate the session when the maximum *number* of prefixes received is exceeded (no such limit is imposed by default). If **restart** is specified, the session will be restarted after *number* minutes. - **max-prefix** *number* **out** \[**restart** *number*\] Terminate the session when the maximum *number* of prefixes sent is exceeded (no such limit is imposed by default). If **restart** is specified, the session will be restarted after *number* minutes. - **multihop** *hops* Neighbors not in the same AS as the local [bgpd(8)](/bgpd/8.md) normally have to be directly connected to the local machine. If this is not the case, the **multihop** statement defines the maximum hops the neighbor may be away. - **passive** Do not attempt to actively open a TCP connection to the neighbor system. - **port** *port* Connect to the peer using *port* instead of the default BGP port 179. - **reject** **as-set** (**yes**\|**no**) If set to **yes**, *AS* *paths* attributes containing *AS\_SET* path segments will be rejected and all prefixes will be treated as withdraws. The default is inherited from the global **reject** **as-set** setting. - **remote-as** *as-number* Set the AS number of the remote system. - **rde** **evaluate** (**default**\|**all**) If set to *all*, keep evaluating alternative paths in case the selected path is filtered out. By default if a path is filtered by the output filters then no alternative path is sent to this peer. The default is inherited from the global **rde** **evaluate** setting. - **rib** *name* Bind the neighbor to the specified RIB. - **role** *role* Set the local role for this eBGP session. Setting a role is required for ASPA verification, the open policy role capability and Only-To-Customer (OTC) attribute of RFC 9234. The role can be one of *none*, *provider*, *customer*, *rs*, *rs-client*, or *peer*. If the role is set to *none* the **announce** **policy** will also be disabled. On iBGP session the role setting is ignored and forced to *none*. - **route-reflector** \[*address*\] Act as an RFC 4456 *route-reflector* for this neighbor. An optional cluster ID can be specified; otherwise the BGP ID will be used. - **set** *attribute* *...* Set the *AS* *path* *attributes* to some default per **neighbor** or **group** block: ``` set localpref 300 ``` See also the ATTRIBUTE SET section. Set parameters are applied to the received prefixes; the only exceptions are **prepend-self**, **nexthop** **no-modify** and **nexthop** **self**. These sets are rewritten into filter rules and can be viewed with “bgpd -nv”. - **staletime** *seconds* Set the upper bound stale time in seconds for graceful restart. Inherited from the global configuration if not given. - **tcp** **md5sig** **password** *secret* - **tcp** **md5sig** **key** *secret* Enable TCP MD5 signatures per RFC 2385. The shared secret can either be given as a password or hexadecimal key. ``` tcp md5sig password mekmitasdigoat tcp md5sig key deadbeef ``` After changing keys, a session needs to be reset to use the new keys. - **transparent-as** (**yes**\|**no**) If set to **yes**, attribute transparency is enabled. See also the **transparent-as** setting in GLOBAL CONFIGURATION. The default is inherited from the global **transparent-as** setting. - **ttl-security** (**yes**\|**no**) Enable or disable ttl-security. When enabled, outgoing packets are sent using a TTL of 255 and a check is made against an incoming packet's TTL. For directly connected peers, incoming packets are required to have a TTL of 255, ensuring they have not been routed. For multihop peers, incoming packets are required to have a TTL of 256 minus multihop distance, ensuring they have not passed through more than the expected number of hops. The default is **no**. ## FILTER [bgpd(8)](/bgpd/8.md) filters all BGP *UPDATE* messages, including its own announcements, and blocks them by default. Filter rules may match on neighbor, direction, *prefix* or *AS* *path* *attributes*. Filter rules may also modify *AS* *path* *attributes*. For each *UPDATE* processed by the filter, the filter rules are evaluated in sequential order, from first to last. The last matching **allow** or **deny** rule decides what action is taken. The default action is to deny. The following actions can be used in the filter: - **allow** The *UPDATE* is passed. - **deny** The *UPDATE* is blocked. - **match** Apply the filter attribute set without influencing the filter decision. ## PARAMETERS The rule parameters specify the *UPDATES* to which a rule applies. An *UPDATE* always comes from, or goes to, one neighbor. Most parameters are optional, but each can appear at most once per rule. If a parameter is specified, the rule only applies to packets with matching attributes. - *as-type* \[*operator*\] *as-number* - *as-type* **as-set** *name* This rule applies only to *UPDATES* where the *AS* *path* matches. The part of the *AS* *path* specified by the *as-type* is matched against the *as-number* or the **as-set** *name*: - **AS** (any part) - **peer-as** (leftmost AS number) - **source-as** (rightmost AS number) - **transit-as** (all but the rightmost AS number) *as-number* is an AS number as explained above under GLOBAL CONFIGURATION. It may be set to **neighbor-as**, which is expanded to the current neighbor remote AS number, or **local-as**, which is expanded to the locally assigned AS number. When specifying an **as-set** *name*, the AS path will instead be matched against all the AS numbers in the set. The *operator* can be unspecified (this case is identical to the equality operator), or one of the numerical operators ``` = (equal) != (unequal) - (range including boundaries) >< (except range) ``` \>\< and - are binary operators (they take two arguments); with these, *as-number* cannot be set to **neighbor-as**. Multiple *as-number* entries for a given type or *as-type* *as-number* entries may also be specified, separated by commas or whitespace, if enclosed in curly brackets: ``` deny from any AS { 1, 2, 3 } deny from any { AS 1, source-as 2, transit-as 3 } deny from any { AS { 1, 2, 3 }, source-as 4, transit-as 5 } ``` - **avs** (**valid** \| **unknown** \| **invalid**) This rule applies only to *UPDATES* where the ASPA Validation State (AVS) matches. - **community** *as-number*:*local* - **community** *name* This rule applies only to *UPDATES* where the **community** path attribute is present and matches. Communities are specified as *as-number*:*local*, where *as-number* is an AS number and *local* is a locally significant number between zero and 65535. Both *as-number* and *local* may be set to ‘\*’ to do wildcard matching. Alternatively, well-known communities may be given by name instead and include **BLACKHOLE**, **GRACEFUL\_SHUTDOWN**, **NO\_EXPORT**, **NO\_ADVERTISE**, **NO\_EXPORT\_SUBCONFED**, and **NO\_PEER**. Both *as-number* and *local* may be set to **neighbor-as**, which is expanded to the current neighbor remote AS number, or **local-as**, which is expanded to the locally assigned AS number. - **large-community** *as-number*:*local*:*local* This rule applies only to *UPDATES* where the **Large** **community** path attribute is present and matches. Communities are specified as *as-number*:*local*:*local*, where *as-number* is an AS number and *local* is a locally significant number between zero and 4294967295. Both *as-number* and *local* may be set to ‘\*’ to do wildcard matching, **neighbor-as**, which is expanded to the current neighbor remote AS number, or **local-as**, which is expanded to the locally assigned AS number. - **ext-community** *subtype* *as-number*:*local* - **ext-community** *subtype* *IP*:*local* - **ext-community** *subtype* *numvalue* - **ext-community** **ovs** (**valid** \| **not-found** \| **invalid**) This rule applies only to *UPDATES* where the *extended* *community* path attribute is present and matches. Extended Communities are specified by a *subtype* and normally two values, a globally unique part (e.g. the AS number) and a local part. Both *as-number* and *local* may be set to **neighbor-as**, which is expanded to the current neighbor remote AS number, or **local-as**, which is expanded to the locally assigned AS number. Wildcard matching is supported for *local*, *numvalue* and *subtype*. If wildcard matching is used on the *subtype* then *numvalue* also needs to be set to ‘\*’. See also the ATTRIBUTE SET section for further information about the encoding. - (**from**\|**to**) *peer* This rule applies only to *UPDATES* coming from, or going to, this particular neighbor. This parameter must be specified. *peer* is one of the following: - **any** Any neighbor will be matched. - **ibgp** All *IBGP* neighbors will be matched. - **ebgp** All *EBGP* neighbors will be matched. - *address* Neighbors with this address will be matched. - **group** *descr* Neighbors in this group will be matched. - **AS** *as-number* Neighbors with this AS will be matched. Multiple *peer* entries may also be specified, separated by commas or whitespace, if enclosed in curly brackets: ``` deny from { 128.251.16.1, 251.128.16.2, group hojo } ``` - (**inet**\|**inet6**) Match only routes in the IPv4 or IPv6 address families, respectively. **inet** is an alias for "prefix 0.0.0.0/0 prefixlen \>= 0"; **inet6** is an alias for "prefix ::/0 prefixlen \>= 0". - **max-as-len** *len* This rule applies only to *UPDATES* where the *AS* *path* has more than *len* elements. - **max-as-seq** *len* This rule applies only to *UPDATES* where a single *AS* *number* is repeated more than *len* times. - **max-communities**\|**max-large-communities**\|**max-ext-communities** *num* This rule applies only to *UPDATES* where the *Basic*, *Large*, or *Extended* *Community* attribute has more than *num* elements. - **nexthop** *address* This rule applies only to *UPDATES* where the nexthop is equal to *address*. The *address* can be set to *neighbor* in which case the nexthop is compared against the address of the neighbor. Nexthop filtering is not supported on locally announced networks and one must take into consideration previous rules overwriting nexthops. - **origin-set** *name* This rule applies only to *UPDATES* that match the given origin-set *name*. - **ovs** (**valid** \| **not-found** \| **invalid**) This rule applies only to *UPDATES* where the Origin Validation State (OVS) matches. - **prefix** *address*/*len* - **prefix** *address*/*len* **prefixlen** *range* - **prefix** *address*/*len* **or-longer** - **prefix** *address*/*len* **maxlen** *mlen* This rule applies only to *UPDATES* for the specified prefix. Multiple entries may be specified, separated by commas or whitespace, if enclosed in curly brackets: ``` deny from any prefix { 192.168.0.0/16, 10.0.0.0/8 or-longer } ``` Multiple lists can also be specified, which is useful for macro expansion: ``` good="{ 192.168.0.0/16, 172.16.0.0/12, 10.0.0.0/8 }" bad="{ 224.0.0.0/4 prefixlen >= 4, 240.0.0.0/4 prefixlen >= 4 }" ugly="{ 127.0.0.1/8, 169.254.0.0/16 }" deny from any prefix { $good $bad $ugly } ``` Prefix length ranges are specified by using these operators: ``` = (equal) != (unequal) < (less than) <= (less than or equal) > (greater than) >= (greater than or equal) - (range including boundaries) >< (except range) ``` \>\< and - are binary operators (they take two arguments). For instance, to match all prefix lengths \>= 8 and \<= 12, and hence the CIDR netmasks 8, 9, 10, 11 and 12: ``` prefixlen 8-12 ``` Or, to match all prefix lengths \< 8 or \> 12, and hence the CIDR netmasks 0–7 and 13–32: ``` prefixlen 8><12 ``` This will match all prefixes in the 10.0.0.0/8 netblock with netmasks longer than 16: ``` prefix 10.0.0.0/8 prefixlen > 16 ``` **or-longer** is a shorthand for: ``` prefix address/len prefixlen >= len ``` **maxlen** *mlen* is a shorthand for: ``` prefix address/len prefixlen <= mlen ``` - **prefix-set** *name* \[**or-longer**\] This rule applies only to *UPDATES* that match the given prefix-set *name*. With **or-longer**, the *UPDATES* will match any prefix in the prefix-set where ``` address/len prefixlen >= len ``` - **quick** If an *UPDATE* matches a rule which has the **quick** option set, this rule is considered the last matching rule, and evaluation of subsequent rules is skipped. - **rib** *name* Apply rule only to the specified RIB. This only applies for received updates, so not for rules using the *to* *peer* parameter. - **set** *attribute* *...* All matching rules can set the *AS* *path* *attributes* to some default. The set of every matching rule is applied, not only the last matching one. See also the following section. ## ATTRIBUTE SET *AS* *path* *attributes* can be modified with **set**. **set** can be used on **network** statements, in **neighbor** or **group** blocks, and on filter rules. Attribute sets can be expressed as lists. The following attributes can be modified: - **community** \[*delete*\] *as-number*:*local* - **community** \[*delete*\] *name* Set or delete the *COMMUNITIES* AS path attribute. Communities are specified as *as-number*:*local*, where *as-number* is an AS number and *local* is a locally significant number between zero and 65535. Alternately, well-known communities may be specified by name: **GRACEFUL\_SHUTDOWN**, **NO\_EXPORT**, **NO\_ADVERTISE**, **NO\_EXPORT\_SUBCONFED**, or **NO\_PEER**. For **delete**, both *as-number* and *local* may be set to ‘\*’ to do wildcard matching. - **large-community** \[*delete*\] *as-number*:*local*:*local* - **large-community** \[*delete*\] *name* Set or delete the *Large* *Communities* path attribute. Communities are specified as *as-number*:*local*:*local*, where *as-number* is an AS number and *local* is a locally significant number between zero and 4294967295. For **delete**, both *as-number* and *local* may be set to ‘\*’ to do wildcard matching. - **ext-community** \[*delete*\] *subtype* *as-number*:*local* - **ext-community** \[*delete*\] *subtype* *IP*:*local* - **ext-community** \[*delete*\] *subtype* *numvalue* - **ext-community** \[*delete*\] **ovs** (**valid** \| **not-found** \| **invalid**) Set or delete the *Extended* *Community* AS path attribute. Extended Communities are specified by a *subtype* and normally two values, a globally unique part (e.g. the AS number) and a local part. The type is selected depending on the encoding of the global part. Two-octet AS Specific Extended Communities and Four-octet AS Specific Extended Communities are encoded as *as-number*:*local*. Four-octet encoding is used if the *as-number* is bigger than 65535 or if the AS\_DOT encoding is used. IPv4 Address Specific Extended Communities are encoded as *IP*:*local*. Opaque Extended Communities are encoded with a single numeric value. The *ovs* subtype can only be set to *valid*, *not-found*, or *invalid*. Currently the following subtypes are supported: ``` bdc BGP Data Collection defgw Default Gateway esi-lab ESI Label esi-rt ES-Import Route Target l2vid L2VPN Identifier mac-mob MAC Mobility odi OSPF Domain Identifier ort OSPF Route Type ori OSPF Router ID ovs BGP Origin Validation State rt Route Target soo Route Origin / Source of Origin srcas Source AS vrfri VRF Route Import ``` Not all type and subtype value pairs are allowed by IANA and the parser will ensure that no invalid combination is created. For **delete**, *subtype*, *numvalue*, or *local*, may be set to ‘\*’ to do wildcard matching. If wildcard matching is used on the *subtype* then *numvalue* also needs to be set to ‘\*’. - **localpref** *number* Set the *LOCAL\_PREF* AS path attribute. If *number* starts with a plus or minus sign, *LOCAL\_PREF* will be adjusted by adding or subtracting *number*; otherwise it will be set to *number*. The default is 100. - **med** *number* - **metric** *number* Set the *MULTI\_EXIT\_DISC* AS path attribute. If *number* starts with a plus or minus sign, *MULTI\_EXIT\_DISC* will be adjusted by adding or subtracting *number*; otherwise it will be set to *number*. - **origin** (**igp**\|**egp**\|**incomplete**) Set the *ORIGIN* AS path attribute to mark the source of this route as being injected from an igp protocol, an egp protocol or being an aggregated route. - **nexthop** (*address*\|**blackhole**\|**reject**\|**self**\|**no-modify**) Set the *NEXTHOP* AS path attribute to a different nexthop address or use blackhole or reject routes. *blackhole* and *reject* only affect the FIB and will not alter the nexthop address. *self* forces the nexthop to be set to the local interface address. If set to *no-modify*, the nexthop attribute is not modified for EBGP multihop sessions. By default EBGP multihop sessions use the local interface address. On other IBGP and directly connected EBGP sessions *no-modify* is ignored. The set *address* is used on IBGP session and on directly connected EBGP session if the *address* is part of the connected network. On EBGP multihop session *no-modify* has to be set to force the nexthop to *address*. ``` set nexthop 192.168.0.1 set nexthop blackhole set nexthop reject set nexthop no-modify set nexthop self ``` - **pftable** *table* Add the prefix in the update to the specified [pf(4)](/pf/4.md) table, regardless of whether or not the path was selected for routing. This option may be useful in building realtime blacklists. - **prepend-neighbor** *number* Prepend the neighbor's AS *number* times to the *AS* *path*. - **prepend-self** *number* Prepend the local AS *number* times to the *AS* *path*. - **rtlabel** *label* Add the prefix to the kernel routing table with the specified *label*. - **weight** *number* The *weight* is used to tip prefixes with equally long AS paths in one or the other direction. A prefix is weighed at a very late stage in the decision process. If *number* starts with a plus or minus sign, the *weight* will be adjusted by adding or subtracting *number*; otherwise it will be set to *number*. *Weight* is a local non-transitive attribute, and is a [bgpd(8)](/bgpd/8.md)-specific extension. For prefixes with equally long paths, the prefix with the larger weight is selected. ## FILES - */etc/bgpd.conf* [bgpd(8)](/bgpd/8.md) configuration file. ## SEE ALSO [strftime(3)](/strftime/3.md), [ipsec(4)](/ipsec/4.md), [pf(4)](/pf/4.md), [rdomain(4)](/rdomain/4.md), [tcp(4)](/tcp/4.md), [bgpctl(8)](/bgpctl/8.md), [bgpd(8)](/bgpd/8.md), [ipsecctl(8)](/ipsecctl/8.md), [isakmpd(8)](/isakmpd/8.md), rc.conf.local(8) ## HISTORY The **bgpd.conf** file format first appeared in OpenBSD 3.5.