duplicate tcp syn messages

Unanswered Question
Oct 7th, 2009

I'm using the ASA for anyconnect users and I keep seeing log messages similar to the following:

4 date=Oct 07 2009 Source IP=10.1.1.201 Source Port=17571 Destination IP=10.0.250.18 Destination Port53887 Duplicate TCP SYN from inside:10.1.1.201/17571 to inside:10.0.250.18/53887 with different initial sequence number

The source changes from various server (so far our Anti-virus server, dns, and Active directory servers) the destination appears to be client ip's that have disconnected.

I would like to stop this as it is filling my logs up with spurious information

I have this problem too.
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dhananjoy chowdhury Wed, 10/07/2009 - 20:54

A duplicate TCP SYN was received during the three-way-handshake that has a different initial sequence number than the SYN that opened the embryonic connection. This could indicate that SYNs are being spoofed. This message occurs in Release 7.0.4.1 and later.

http://www.cisco.com/en/US/docs/security/asa/asa71/system/message/logmsgs.html?bcsi_scan_73B62AB387D5D02C=0&bcsi_scan_filename=logmsgs.html#wp3456474

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