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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [FW-1] SMTP and Unknown Established TCP packet
Thanks James. U did solve my problem to a greater extent. And increasing the timer (tcpstarttimeout) to 300 sec did work. but is it advisable to put a such a large value ? I am little worried there. Anybody has any comments? James Schnack <[email protected]> Sent by: Mailing list for discussion of Firewall-1 <[email protected]> 03/27/2002 07:47 PM Please respond to Mailing list for discussion of Firewall-1 To: [email protected] cc: (bcc: subscriptions/ITD/GHO/DFCC) Subject: Re: [FW-1] SMTP and Unknown Established TCP packet I did experience that problem some time back, at a customer of ours. We found out that SMTP connections to many sites took *long* times to establish. We demonstrated that in that particular case the problem was lousy service from the ISP, since many sites had problems when connections were attempted. Connections were being dropped (out of state) since it took longer than the "handshake" timeout to start exchanging traffic. We worked-around it taking the 60s default timer to 300s, and advised the customer to talk to their service provider. If you want to make sure, download VisualRoute, install it on a laptop and place it just outside the FW with a public IP. Then point VR to some of the problematic sites and you may eventually see routing loops or long delays on specific links on the way to them. They have a handy 30d eval version at http://www.visualware.com/download/index.html. At that time, Lance Spitzner's paper on how FW-1's connection table works (http://www.enteract.com/~lspitz/fwtable.html) proved extremely useful. We monitored the FW's connection table (with a Perl script that converts the hex to decimal) while simultaneously sniffing traffic to find the cause of the problem. But of course, that was not a Windows box... ;-) Who knows, maybe you are experiencing that same problem. Let us know how it went! J. >From: [email protected] >Reply-To: Mailing list for discussion of Firewall-1 ><[email protected]> >To: [email protected] >Subject: [FW-1] SMTP and Unknown Established TCP packet >Date: Wed, 27 Mar 2002 11:29:51 +0600 > >Hi, > >I have very simple checkpoint installation with a mail gateway on DMZ. >most of my SMTP mail keeps dropping with the "Unknown Established TCP >packet" - both inbound and outbound. to rectify this I have done the >following on the fw (ver 4.1 SP6 running on NT 4.0) > >In objects.c I have increased the tcpstarttimeout to 120 sec from default >60 sec >On init.def file I have added ADD_TCP_TIMEOUT (25,3600) >(Both tips I got from phoneboy) > >But my problem is not solved. The smtp drops have slightly decreased but >not significantly. > >When I put the smtp traffic on fast mode my problem is solved. no dropped >smtp packets! . But I dont feel this is the correct way to go about it. > >So > >1. What else can I do rectify this problem other than activation fast >mode? I am willing try any wild idea. >2. If my only solution is to activate fast mode , then how risky is it (or >in other words is it not recommended) ? > >Thanks in advance > > >Nishan > >================================================= >To set vacation, Out Of Office, or away messages, >send an email to [email protected] >in the BODY of the email add: >set fw-1-mailinglist nomail >================================================= >To unsubscribe from this mailing list, >please see the instructions at >http://www.checkpoint.com/services/mailing.html >================================================= >If you have any questions on how to change your >subscription options, email >[email protected] >================================================= _________________________________________________________________ Send and receive Hotmail on your mobile device: http://mobile.msn.com ================================================= To set vacation, Out Of Office, or away messages, send an email to [email protected] in the BODY of the email add: set fw-1-mailinglist nomail ================================================= To unsubscribe from this mailing list, please see the instructions at http://www.checkpoint.com/services/mailing.html ================================================= If you have any questions on how to change your subscription options, email [email protected] ================================================= ================================================= To set vacation, Out Of Office, or away messages, send an email to [email protected] in the BODY of the email add: set fw-1-mailinglist nomail ================================================= To unsubscribe from this mailing list, please see the instructions at http://www.checkpoint.com/services/mailing.html ================================================= If you have any questions on how to change your subscription options, email [email protected] =================================================
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