--- name: "h2n" section: "1" platform: "linux" package: "bind" version: "1:8.4.7-1" release: "Debian 4.0 (Etch)" platforms: ["linux"] url: "https://new.carta.tech/h2n" --- # h2n(1) Translate host table to name server file format ## NAME h2n - Translate host table to name server file format ## SYNOPSIS **h2n** -d *DOMAIN* -n *NET* -u *CONTACT* \[options\] ## DESCRIPTION **h2n** translates */etc/hosts* to DNS files and creates a BIND boot file. This tool can be run once or many times. After converting your host table to DNS format, you can manually maintain the DNS files, or you can maintain the host table and run **h2n** each time you modify */etc/hosts*. **h2n** automatically increments the serial number in each DNS file when it makes a new one. **h2n** generates files starting with the prefix "db." These are called "db files." The domain data are stored in a file called db.DOMAIN, where DOMAIN defaults to the first label in your domain name (given with the **-d** option). The address-to-name data are stored in files named db.NET, where NET is a network number (given with the **-n** option). An email address for the person responsible for the domain is included in the start-of-authority record for the domain (given with the **-u** option). Each time **h2n** is run, it generates the DNS files from scratch. Any changes you manually made to the DNS files are lost. If you'd like to add resource records to a db file generated by **h2n**, put your RRs in a file prefixed with "spcl" instead of "db". **h2n** will include this file's data by adding an $INCLUDE directive to the end of the db file. By default, **h2n** will generate an MX record with a weight of 10 that points to the host itself as the mail exchanger. Additional MX records can be added to all hosts by using **-m** options. To suppress generating the default MX record for a host, include "\[no smtp\]" in that host's host table comment. Note that "\[no smtp\]" does not override **-m** options. Use "\[no mx\]" in the comment field to suppress all MX record generation for that host. This is useful for such IP devices as printers which do not need mailer information. In conjunction with "\[no mx\]", you can add the "\[smtp\]" flag in the comment field to have only the default MX record added, suppressing **-m** options for the host. All MX record generation for the domain can be suppressed with **-M**. Another comment section flag is "\[TTL=**num**\]", where **num** is a specific time-to-live value to use for the resource records pertaining to the canonical hostname in the host table. This is useful for setting artificially high or low TTL values for individual hosts. For example, if you are going to be moving a host to a new IP address, you can use this to set a low TTL value such as 900 (seconds). This limits how long the old IP address will be cached everywhere. The maximum any client will have to wait for the new IP address to be seen would be 15 minutes in this case. There is one additional comment field option which causes certain records to be created or not created. Including "\[rafcp\]" in the comment section will cause WKS records indicating RAFCP support to be generated for the host and suppress generation of all MX records, even those specified with the **-m** option. This is to support routable AFCP on the TIO-side of HP 3000s which use Telnet Express Boxes as front ends. By default, **h2n** will create a boot file, *./boot.cacheonly*, for a caching-only name server. If either of the **-z** or **-Z** options are used, **h2n** creates a boot file, named *./boot.sec.save* or *./boot.sec* respectively, for a secondary name server. NOTE: Certain **h2n** options (**-v**, **-I audit**) require that the *dig*\ program be installed. *dig* is available in the standard BIND\ distribution at \< http://www.isc.org/products/BIND/ \>. - Options are: - **-A** Don't create name server data for aliases in the host table. - **-a** *NET\[:SUBNETMASK\] \[NET\[:SUBNETMASK\]\] ...* Add information about hosts from network NET to the DOMAIN database file. This is similar to the -n option, but no PTR data is generated, i.e., no db.NET file is created. This is useful when another server is responsible for address-to-name mapping, but this server is responsible for name-to-address mapping. Including more than one -a option is allowed. - **-b** *BOOTFILE* Use BOOTFILE instead of the default: *./named.boot* - **-B** *PATH* Sets the directory where boot files will be written (named.boot, boot.sec and/or boot.sec.save, and boot.cacheonly). You must specify an absolute pathname. - **-c** *REMOTE-DOMAIN \[mode=\[A\]\[D\[Q\]\]\] \[REMOTE-DOMAIN\] ...* Create CNAME records in the default domain for all the hosts in REMOTE-DOMAIN. These CNAME records are generated before any other data in the default DOMAIN specified in the -d option, i.e, RR name conflicts favor the -c REMOTE-DOMAIN over the default DOMAIN. Also, CNAME records are only generated for canonical names in REMOTE-DOMAIN - aliases are ignored. This default behavior can be overridden by including one or more of the following *mode=* flags:\ A Create additional CNAMEs for aliases in REMOTE-DOMAIN.\ D Defer creation of CNAMEs, i.e., RR names in the default\ DOMAIN takes precedence over naming conflicts in the\ REMOTE-DOMAIN.\ Q Do not issue a warning message when a deferred CNAME\ can not be created due to a naming conflict in the default\ domain. Valid only when the "D" flag is also specified. Including more than one -c option is allowed. - **-C** *COMMENT-FILE* Create resource records by using keys in the host table comment field as indices into COMMENT-FILE. COMMENT-FILE contains "key:resource record" pairs like: "720:IN HINFO hp9000s720 hp-ux". When **h2n** encounters "720" in the comment section of the host table, it creates a resource record by replacing the "720:" with the host's canonical name. - **+c** *CONFFILE* Use CONFFILE instead of the default: *./named.conf* - **-d** *DOMAIN \[db=FILE1\] \[spcl=FILE2\] \[mode=d\]* Your domain name is DOMAIN. Use the *db=* and/or *spcl=* arguments to override the default filenames of db.LABEL and spcl.LABEL where LABEL is the first label of DOMAIN, e.g., *label*.movie.edu. Use the *mode=d* argument to set the default domain of unqualified canonical host names in the hostfile to DOMAIN. - **-e** *EXCLUDED-DOMAIN \[EXCLUDED-DOMAIN\] ...* Exclude data from the hostfile with names in EXCLUDED-DOMAIN. Specifying more than one -e option is allowed. - **-f** *FILE* Command line options are read from a file called FILE. This option cannot be used within FILE. Comments are allowed in FILE using the same style as in the host table or DNS database files, i.e., comments start after a '#' or ';' and continue to the end of the line. - **-h** *HOST* Use HOST in the MNAME (master nameserver) field of the SOA record. The default is the host on which you run **h2n**. - **-H** *HOSTFILE* Use HOSTFILE instead of */etc/hosts*. - **-i** *NUM* Set the serial number of the zone to NUM. - **-I** *\[ignore\|warn\|audit\|warn-strict\|fail\|strict\]* Controls the level of checking done on hostnames for conformance to naming standards established by RFC-952 and RFC-1123. The -I option accepts one of the following arguments which are ordered such that each subsequent argument includes the functionality of the preceding one:\ ignore Disables name checking.\ warn Issues a warning about hostnames and domain names that\ do not conform to RFC-952 and RFC-1123.\ NOTE: Hostname aliases that generate a CNAME record\ type (the most common case) are generally not subject\ to the restrictions of these two RFCs.\ This flexibility of alias names allows the preservation\ of an otherwise illegal hostname by making it become an\ alias instead.\ audit Issues a warning about -h/-s/-S/-m options that point\ to CNAMEs or nonexistent domain names. If a 'spcl'\ forward-mapping file exists, the same checks are also\ done with NS, MX and PTR records as well as checks for\ dangling CNAMEs. Delegated subdomains are checked for\ having at least two listed nameservers, no missing glue\ records, and NS RRsets with consistent TTL values.\ This is the default setting.\ warn-strict Extends conformance checking to the RFC-952 requirement\ that hostnames and their aliases in the host table be\ at least two characters in length.\ fail Performs the same level of checking as the *warn*\ argument except that non-compliant hostnames and\ aliases are rejected.\ strict Performs the same level of checking as the *warn-strict*\ argument except that non-compliant hostnames and\ aliases are rejected. - **-L** *NUM* Explicitly use a file handle limit of NUM when generating database files. - **+L** *\[LOG-SPEC\]* Add a logging specification to the config files (named.conf, conf.sec, conf.sec.save). If you only specify "+L", you'll get a simple logging specification that will eliminate a lot of bogus information that would otherwise fill up your syslog. You can override this by giving your own entries, e.g., "+L category lame-servers { null; };". For each "+L LOG-SPEC" option you add, a line containing LOG-SPEC is added in the config file, thus including more than one +L option is allowed. See the **named(1M)** man page for valid logging options. - **-m** *WEIGHT:MX-HOST \[WEIGHT:MX-HOST\] ...* Include an MX record for each host in your domain pointing to MX-HOST at WEIGHT. Including more than one -m option is allowed. - Example: -m 10:terminator.movie.edu 20:wormhole - **+m** *\[D\|C\|P\|CP\]* Controls the method by which DNS records get generated for hosts with multiple addresses. By default, the canonical name of such multi-homed hosts is assigned an 'A' record for each address. Aliases unique to one address are also assigned an 'A' record. Aliases common to all addresses are assigned a CNAME record. The PTR record for each address points to the multi-address canonical name. This default behavior can be overridden by specifying one of the following flags:\ D Same as the default behavior.\ C The first alias unique to one address is still assigned\ an 'A' record but subsequent aliases unique to the address\ are assigned CNAME records which point to the first alias.\ P PTR records do not point to the multi-address canonical name\ but instead point to the first alias having an 'A' record. Combining the *C* and *P* flags is allowed. These global specifications can be overridden for any host by including the analogous "\[mh=d\|c\|p\|cp\]" flag in its comment field. - **-M** Don't generate MX records. - **-n** *NET\[:SUBNETMASK\] \[NET\[:SUBNETMASK\]\] ...* NET is your network number without the trailing zeros. Including more than one -n option is allowed. If SUBNETMASK is provided, create data for each subnet of NET. - Example: -n 192.249.249 15.15.16:255.255.248.0 - **-N** *SUBNETMASK* Apply SUBNETMASK to all network numbers instead of listing each subnet with -n. Specifying a subnet mask with -n overrides the -N subnet mask for that network only. - **-o** *\[REFRESH\]:\[RETRY\]:\[EXPIRE\]:\[MINIMUM\]:\[DEFAULT-TTL\]* Change the default SOA values to the values provided. For nameservers running versions of BIND prior to 8.2, the default values are (10800:3600:604800:86400). For versions 8.2 and later which implement RFC-2308, the defaults are (3h:1h:1w:10m:1d) with *DEFAULT-TTL* appearing in a $TTL directive and *MINIMUM* being semantically treated as a negative caching value . If *DEFAULT-TTL* is not specified, **h2n** will try to determine the BIND version of the master nameserver (-h option or localhost) and act accordingly. NOTE: These built-in default values do not override those in zone\ files that already exist. Use the -o option to specify SOA\ values that will override those in existing zone files as\ well as becoming the default values for new zone files. - Example: -o ::::8h generates *$TTL 8h* in all zone files. - **-O** *OPTION OPTION-ARGS* Add a boot option specification to the boot files (named.boot, boot.sec, boot.sec.save), e.g., "-O options no-round-robin". See the **named** man page for valid options. Including more than one -O option is allowed. - **+O** *\[OPTION-SPEC\]* Add an option section specification to the config files (named.conf, conf.sec, conf.sec.save), e.g., "+O round-robin no;". See the **named** man page for valid options. Including more than one +O option is allowed. For each "+O OPTION-SPEC", a new line containing OPTION-SPEC is added to the config file. If you use a single +O option without an argument, the global options section will not be generated. This is useful if you want to maintain a main named.conf file for your master and slaves with a complex mix of options {}, logging {}, and other global sections, and 'include' the **h2n**-generated zone sections. Combine this with a +c option. - **+om** *OPTION OPTIONS-ARGS* Adds a zone-specific option to the config file (named.conf), e.g., "+om also-notify { 15.1.2.3; 15.1.2.4; };". This option is position dependent and applies to the last -d or -n option specified, however, if a +om option appears before any -d or -n options it is assumed that the +om option applies to all zones. Thus, it will be added to each zone section in the config file. - **+os** *OPTION OPTIONS-ARGS* Adds a zone-specific option to the config files (conf.sec and/or conf.sec.save), e.g., "+os max-transfer-time-in 60;". Like the +om option, it is position dependent and applies to the last -d or -n option specified. Also, if a +os option appears before any -d or -n options it is assumed that the +os applies to all zones. - **-p** *REMOTE-DOMAIN \[mode=\[A\]\[P\]\] \[REMOTE-DOMAIN\] ...* Create only PTR data for hosts in REMOTE-DOMAIN. This is useful when a different server is responsible for the forward (name-to-address) mapping data of REMOTE-DOMAIN but this server is responsible for the reverse (address-to-name) mapping data of each -n option. Including more than one -p option is allowed. The *mode=* argument may need to be specified with one of the following flags:\ A Required for each REMOTE-DOMAIN which had its forward\ mapping data built with the -A option. This prevents\ dangling PTR records from being generated for multi-homed\ hosts in REMOTE-DOMAIN having the "\[mh=p\]" or "\[mh=cp\]" flag\ in the comment field. Can also be specified as an override\ flag for REMOTE-DOMAIN when the '+m P' option is in effect.\ P Enables the alternate method of PTR record generation for\ multi-homed hosts in REMOTE-DOMAIN as previously described\ for the '+m P' option when that option is \*not\* in effect.\ This method is overridden for any host in REMOTE-DOMAIN\ having the "\[mh=d\]" or "\[mh=c\]" flag in its comment field. - **-q** Work quietly. - **-r** Enable creation of RP (Responsible Person) records. Look for strings in the comment section of the host table that match "\[rp=**mail-addr** **\[text\]**\]", where **mail-addr** is a usual e-mail address specification, and (optionally) **text** is a free-form text string (usually containing a phone number and/or pager number, or other info). This construct is converted to an RP record containing the e-mail address, and if **text** is present, a TXT record is also added containing **text** (with the RP record referencing the TXT record). - **-s** *SERVER \[SERVER\] ...* List SERVER for all zones. Adds NS records for the zone(s) corresponding to the -d option and all -n options. Including more than one -s option is allowed. - **-S** *SERVER \[SERVER\] ...* List SERVER for specific zone(s). Adds NS records for the zone(s) corresponding to the last preceding -d or -n option (this option is position dependent). There can be multiple zones if this applies to a -n option. Including more than one -S option is allowed. - **-t** Generate TXT records from the host table comment section. Any special processing options are ignored, e.g., \[no smtp\]. - **+t** *DEFAULT-TTL \[MINIMUM-TTL\]* Create RFC-2308 $TTL directives in all zone files. If MINIMUM-TTL is specified, use that instead of the default of 10 minutes (600). - **-u** *USER* Use USER as the e-mail address in the RNAME (responsible person) field of the SOA record. USER should be a complete mail address, e.g., me@a.b.c . Defaults to root@DOMAIN (-d option). Periods in the username-portion of the address, e.g., first.last@a.b.c , will be escaped if necessary. NOTE: If USER lacks the "@" symbol and has a trailing period,\ RNAME format will be assumed and USER left unchanged. - **-v** *domain \[domain\]* Verify the integrity of a domain by performing a zone transfer and analyzing the data. All of the checks described above for the *-I audit* option are done plus those for "CNAME and other data" errors. In addition, listed nameservers are checked for proper delegation. - **-w** Generate WKS records that list the SMTP service over the TCP protocol if an MX record is also created. - **-W** *PATH* Sets the directory where db files will be located on the primary and secondary name servers. This is useful if you build new db files on a host other than the primary. You must specify an absolute pathname. - **-y** Use the date to create the serial number. The date format used is YYYYMMDDXX. YYYY is the year. MM is the month. DD is the day of the month. XX is counter that starts at 00 and increments each time **h2n-hp** is run on the same day. The -y option will be ignored for zones in which the existing serial number is larger than the computed date-based serial number. - **-z** *ADDRESS \[ADDRESS\]* Create a boot file, *./boot.sec.save*, for a secondary name server that lists ADDRESS as the master to load from, and save a copy of the zone data in a backup file. (This option is similar to the -Z option.) Including more than one -z option is allowed. - **-Z** *ADDRESS \[ADDRESS\]* Create a boot file, *./boot.sec*, for a secondary name server that lists ADDRESS as the master to load from, and do not save a copy of the data in a backup file. (This option is similar to the -z option.) Including more than one -Z option is allowed. - **-recurse** Enables delegated subdomains to be recursively verified after completing verification of the parent domain with the -v option. - **-no-check-del** Disables delegation checking when verifying one or more domains with the -v option. Such checks can take a long time if a large number of unresponsive nameservers are encountered. - **-show-chained-cnames** Displays each element of a CNAME chain to which an out-of-zone CNAME points. The default behavior is to ignore CNAME chains that successfully resolve and display just the chain length of dangling or looping CNAMEs. ## EXAMPLES Create name server data for networks 192.249.249 and 192.253.253 in movie.edu. h2n -d movie.edu -n 192.249.249 -n 192.253.253 Create name server data for networks 192.249.249 and 192.253.253 in movie.edu. Eliminate lines in the host table that contain fx.movie.edu and include MX records for all hosts pointing to the mail hub, postmanrings2x.movie.edu. Afterwards, look for additional resource records in the file "spcl.movie.edu" and append them to "db.movie" via an $INCLUDE directive. Include all of the options in a file. h2n -f option\_file option\_file contains the following lines: \-d movie.edu spcl=spcl.movie.edu -n 192.249.249 -n 192.253.253 -e fx.movie.edu -m 50:postmanrings2x.movie.edu