|
|
|
|
|
|
|
|
 |
 |
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [FW-1] SMTP server communication and "unknown established TCP packet"
Hello Christian, CB> the mailserver in DMZ cannot transfer Emails to internal Mailserver. FW-1 log entry: drop; unknown established TCP packet. I know what this means, but how can I change this? Everything is allowed CB> between both servers. I already tested with NAT, but without positiv results. I don't know if this is your situation ; but i've already seen that somewhere. This situation happens when the mail server is extremely overloaded. By default, I think CKP FW1 waits for maximum 60 secs for an ACK after a SYN. On the internet, it happenned to us that some extremely popular mail servers (namely : hotmail) are not that "fast", and their answers are sometimes dropped for "unknown extab tcp packet" because their ACK comes in when the SYN has been tossed out of the state table already. I think this setting can be tuned (this *IS NOT* the "tcp timeout" value, you have to hack into the EXPECT to change what i'm speaking about), but I would not recommend doing it as 60 secs is already an extremely pessimistic value. In our case, mail to hotmail just waits a bit to get delivered, their server has no exucse for beeing so slow. You should also check about possible assymetric routing on your network, but I don't know about it so it's just an idea. -- http://techos.org ISP Techie Community Website ================================================= 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] =================================================
|
||||||||||
 |
 |
 |
 |
 |
 |
 |
 |
 |
|
