tcpdump will not compile with ability to decrypt ESP encapsulated packets.

Crist J. Clark cristjc at comcast.net
Thu Dec 4 21:28:14 PST 2003


On Tue, Dec 02, 2003 at 10:28:52AM -0700, Dr Otacon wrote:
> I'm trying to tcpdump ESP encapsulated packets with tcpdump using:
> 
>     tcpdump -w tcpdump.log -E blowfish-cbc:secret esp host safehost

Tcpdump(8) does not decrypt as it saves data in the pcap dump file. It
only decrypts on the fly as it prints packet contents.

> ...but `tcpshow < tcpdump.log' has this message repeated at the end of every 
> packet:
> 
>     <*** No decode support for encapsulated protocol ***>

Tcpshow(1) would have to decrypt the ESP data itself for this to
work.
-- 
Crist J. Clark                     |     cjclark at alum.mit.edu
                                   |     cjclark at jhu.edu
http://people.freebsd.org/~cjc/    |     cjc at freebsd.org


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