---
name: "fragroute"
section: "8"
platform: "linux"
package: "fragroute"
version: "1.2-7.1"
release: "Debian 4.0 (Etch)"
platforms: ["linux"]
url: "https://new.carta.tech/fragroute"
---

# fragroute(8)

intercept, modify, and rewrite egress traffic

## NAME

fragroute - intercept, modify, and rewrite egress traffic

## SYNOPSIS

**fragroute** \[**-f** *file*\] *host*

## DESCRIPTION

**fragroute** intercepts, modifies, and rewrites egress traffic destined for the specified  *host*, implementing most of the attacks described in the Secure Networks \`\`Insertion, Evasion, and Denial of Service: Eluding Network Intrusion Detection'' paper of January 1998.

The options are as follows:

- **-f** *file*

  Read ruleset from the specified  *file* instead of  */etc/fragroute.conf*.

Unlike [**fragrouter**(8)](/fragrouter/8.md), this program only affects packets originating from the local machine destined for a remote *host*. Do not enable IP forwarding on the local machine.

## RULESET

**fragroute** is composed of several modules which enable various configuration directives. Each directive operates on a logical packet queue handed to it by the previous rule.

- **#** *string ...*

  Ruleset comment, no-op.

- **delay first**\|**last**\|**random** ***ms***

  Delay the delivery of the first, last, or a randomly selected packet from the queue by  *ms* milliseconds.

- **drop first**\|**last**\|**random** ***prob-%***

  Drop the first, last, or a randomly selected packet from the queue with a probability of *prob-%* percent.

- **dup first**\|**last**\|**random** ***prob-%***

  Duplicate the first, last, or a randomly selected packet from the queue with a probability of *prob-%* percent.

- **echo** *string ...*

  Echo the  *string* argument(s) to standard output.

- **ip\_chaff dup**\|**opt**\|***ttl***

  Interleave IP packets in the queue with duplicate IP packets containing different payloads, either scheduled for later delivery, carrying invalid IP options, or bearing short time-to-live values.

- **ip\_frag** *size* \[**old**\|**new**\]

  Fragment each packet in the queue into  *size*-byte IP fragments, preserving the complete transport header in the first fragment. Optional fragment overlap may be specified as **old** or **new**, to favor newer or older data.

- **ip\_opt lsrr**\|**ssrr** *ptr ip-addr ...*

  Add IP options to every packet, to enable loose or strict source routing. The route should be specified as list of IP addresses, and a bytewise pointer into them (e.g. the minimum *ptr* value is 4).

- **ip\_ttl** *ttl*

  Set the IP time-to-live value of every packet to *ttl*.

- **ip\_tos** *tos*

  Set the IP type-of-service bits for every packet to *tos*.

- **order** **random**\|**reverse**

  Re-order the packets in the queue randomly, or in reverse.

- **print**

  Print each packet in the queue in tcpdump-style format.

- **tcp\_chaff** **cksum**\|**null**\|**paws**\|**rexmit**\|**seq**\|**syn**\|***ttl***

  Interleave TCP segments in the queue with duplicate TCP segments containing different payloads, either bearing invalid TCP checksums, null TCP control flags, older TCP timestamp options for PAWS elimination, faked retransmits scheduled for later delivery, out-of-window sequence numbers, requests to re-synchronize sequence numbers mid-stream, or short time-to-live values.

- **tcp\_opt** **mss**\|**wscale** *size*

  Add TCP options to every TCP packet, to set the maximum segment size or window scaling factor.

- **tcp\_seg** *size* \[**old**\|**new**\]

  Segment each TCP data segment in the queue into *size*-byte TCP segments. Optional segment overlap may be specified as **old** or **new**, to favor newer or older data.

## EXAMPLES

Fragment all traffic to a Windows host into forward-overlapping 8-byte fragments (favoring older data), reorder randomly, and print to standard output:

```
	ip_frag 8 old
	order random
	print
```

Segment all TCP data to a host into forward-overlapping 4-byte segments (favoring newer data), interleave with overwriting, random chaff segments bearing older timestamp options for PAWS elimination, reorder randomly, and print to standard output:

```
	tcp_seg 4 new
	tcp_chaff paws
	order random
	print
```

## FILES

- */etc/fragroute.conf*

  Default configuration ruleset

## SEE ALSO

[**fragtest**(8)](/fragtest/8.md)

## AUTHOR

Dug Song \<dugsong@monkey.org\>

## BUGS

It is entirely possible to mangle your outgoing traffic so badly that no remote TCP/IP stack will accept it. K.I.S.S.