Firewall Wizards mailing list archives
Re: Source of T/TCP traffic
From: Knut Bjornstad <kbjo () interpost no>
Date: Tue, 9 Sep 2003 14:29:42 +0200
On Tue, Sep 09, 2003 at 02:22:58PM +0200, Volker Tanger wrote:
Greetings! On Tue, 9 Sep 2003 Knut Bjornstad <kbjo () interpost no> wrote:Our IDS are seeing a lot of peculiar T/TCP traffic - the alerts on this is no problem in itself - I can easily disable them. But when I try to analyze the traffic, it seems like ordinary web traffic from various MS IE sources.Do you see T/TCP, TAO or the braindead MS-IE/IIS speedup hack? Usually newer IE try to send the HTTP request already in the SYN packet (or was it first sending an ACK packet with the request?) ignoring the usual need for a SYN - SYN/ACK - ACK handshake for a proper TCP connection. While the IIS answers directly other servers respond with a RST, upon which the IIS starts anew with the standard 3-way handshake. This way a MS-IE/MS-IIS pair has a small speed advantage over standard clients or servers. It's called improving industry standards, I fear. If this is the traffic you see, you can safely ignore it (as MS-IE does). HTH Volker Tanger
What I see is SYN packets with the ccnew TCP option set. I don't see a full TAO since we don't have T/TCP. I do not fully know the MS-IE/IIS speedup hack, but that is different isn't it? I have some indication that this is some netdevice changing the traffic. The browser field in my access logs report varying versions of MSIE, so I think the adresses are NAT'ed for several clients. -- --Knut Bjornstad -- ErgoIntegration AS ---Oslo, Norway------- --kbjo () interpost no -- t:47 23 14 53 36 -- mob: 901 15 917 -- _______________________________________________ firewall-wizards mailing list firewall-wizards () honor icsalabs com http://honor.icsalabs.com/mailman/listinfo/firewall-wizards
Current thread:
- Source of T/TCP traffic Knut Bjornstad (Sep 09)
- Re: Source of T/TCP traffic Volker Tanger (Sep 11)
- Re: Source of T/TCP traffic Knut Bjornstad (Sep 11)
- Re: Source of T/TCP traffic Knut Bjornstad (Sep 12)
- RE: Source of T/TCP traffic lordchariot (Sep 12)
- Re: Source of T/TCP traffic Mikael Olsson (Sep 12)
- <Possible follow-ups>
- RE: Source of T/TCP traffic Dave Killion (Sep 11)
- Re: Source of T/TCP traffic Volker Tanger (Sep 11)