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====== TCPRewriter Element Documentation ======

===== NAME =====

**TCPRewriter** -- Click element;
rewrites TCP packets' addresses, ports, and sequence numbers

===== SYNOPSIS =====

TCPRewriter(INPUTSPEC1, ..., INPUTSPECn [, KEYWORDS])

**Ports**: 1 or more inputs, 1-256 outputs\\ 
**Processing**: push\\ 
**Package**: tcpudp (core)\\ 

===== DESCRIPTION =====

Rewrites TCP flows by changing their source address, source port, destination
address, and/or destination port, and optionally, their sequence numbers and
acknowledgement numbers. It also changes the destination IP address
annotation; see the DST_ANNO keyword argument below.
This element is an [[IPRewriter]]-like element. Please read the [[IPRewriter]]
documentation for more information and a detailed description of its
INPUTSPEC arguments.
In addition to [[IPRewriter]]'s functionality, the TCPRewriter element can add or
subtract amounts from incoming packets' sequence and acknowledgement numbers,
including any SACK acknowledgement numbers. Each newly created mapping starts
with these deltas at zero; other elements can request changes to a given
mapping. For example, [[FTPPortMapper]] uses this facility.
Keyword arguments determine how often stale mappings should be removed.


 ? **TCP_TIMEOUT //time//**
 ! Time out TCP connections every //time// seconds. Default is 24 hours.

 ? **TCP_DONE_TIMEOUT //time//**
 ! Time out completed TCP connections every //time// seconds. Default is 30
seconds. FIN and RST flags mark TCP connections as complete.

 ? **REAP_TCP //time//**
 ! Reap timed-out TCP connections every //time// seconds. If no packets
corresponding to a given mapping have been seen for TCP_TIMEOUT, remove the
mapping as stale. Default is 1 hour.

 ? **REAP_TCP_DONE //time//**
 ! Reap timed-out completed TCP connections every //time// seconds. Default is 10
seconds.

 ? **DST_ANNO**
 ! Boolean. If true, then set the destination IP address annotation on passing
packets to the rewritten destination address. Default is true.


===== ELEMENT HANDLERS =====


 ? **mappings (read-only)**
 ! Returns a human-readable description of the TCPRewriter's current set of
mappings.


===== SEE ALSO =====

[[IPRewriter]], [[IPAddrRewriter]], [[IPAddrPairRewriter]], [[IPRewriterPatterns]],
[[FTPPortMapper]]


Generated by 'click-elem2man' from '../elements/tcpudp/tcprewriter.hh' on 24/May/2007.


===== COMMENTS =====