comp.os.linux.networking

On Sat, 22 Mar 2008 20:22:23 -0700, buck wrote:

> On Sat, 22 Mar 2008 15:57:57 GMT, Jack Snodgrass
> wrote:
>
>>There are a couple of mail servers - charter.net and
>>mta.email.ichotelsgroup.com that give me the timeout after DATA from
>>message in my mail.log.
>>
>>I am running post fix.
>>
>>I get lots of mail from other servers... but these two keep trying over
>>and over again and give me these timeout messages.
>>
>>Any idea what might be causing this?
>>
>>Any postfix gurus that can suggest a setting I can tweak.
>>
>>This is going via a tunnel from a fixed ip address to my mail server on
>>the other end of the tunnel. mail from gmail and my office and other
>>sites don't have issues.. my log just shows charter.net and
>>ichotelsgroup.com as servers having issues.
>>
>>jack
> I'm no postfix guru, though I do run it.
>
> I'd suggest that you try a Wireshark dump. Since other mtas are able to
> talk, then suspect a firewall setting or other foreign interference. It
> certainly isn't impossible that you have something weird in your postfix
> setup, but for it to be so specific would be unusual.
>
> charter.net has been on (and off again) many black hole lists. I don't
> know its current status, but you should see if others also have a
> problem with it.
>
> If you have ECN (congestion) enabled, make sure that isn't a problem for
> some router in the path.


Not sure how this will cut/paste.... I changed the domains and email
addresses... and replaced the local ip with L and the remote with R.
The rest is as-is....

L R SMTP Response: 220 home.example.com ESMTP Postfix
R L TCP 51499 > smtp [ACK] Seq=1 Ack=43 Win=33304 Len=0
TSV=1776034838 TSER=2021657217
R L SMTP Command: EHLO que03.charter.net
L R TCP smtp > 51499 [ACK] Seq=43 Ack=25 Win=91 Len=0
TSV=2021657480 TSER=1776034838
L R SMTP Response: 250-home.example.com
R L TCP 51499 > smtp [ACK] Seq=25 Ack=186 Win=33304 Len=0
TSV=1776034849 TSER=2021657480
R L SMTP Command: MAIL FROM: SIZE=3430
L R SMTP Response: 250 2.1.0 Ok
R L SMTP Command: RCPT TO:
L R TCP smtp > 51499 [ACK] Seq=200 Ack=102 Win=91 Len=0
TSV=2021657770 TSER=1776034866
L R SMTP Response: 250 2.1.5 Ok
R L SMTP Command: DATA
L R TCP smtp > 51499 [ACK] Seq=214 Ack=108 Win=91 Len=0
TSV=2021657872 TSER=1776034888
L R SMTP Response: 354 End data with .
R L SMTP DATA fragment, 1120 bytes
R L SMTP [TCP Previous segment lost] DATA fragment, 862 bytes
L R TCP smtp > 51499 [ACK] Seq=251 Ack=1228 Win=126 Len=0
TSV=2021658042 TSER=1776034898 SLE=2676 SRE=3538
L R SMTP Response: 421 4.4.2 home.example.com Error: timeout exceeded

... is that enough data for someone to tell anything? An email from
gmail.com does something similar except for the
R L SMTP [TCP Previous segment lost] DATA fragment, 862 bytes
packet... I don't get that.. I get a couple of DATA Fragment packets,
I ACK them and the mail session closes normally.


jack




--