Fetchmail, gmail and TCP RST

Leonid.I · 2010-08-31 16:03:01

Hi archers,

For quite a long time I have been experiencing an annoying issue with my fetchmail + gmail setup.

The fetchmail config is as usual

set daemon 900
poll imap.gmail.com proto IMAP no dns
user 'xxxxx' there is 'yyyyy' here
ssl

This works, i.e. every 15 min I fetch messages from gmail, but there is also a simultaneous iptables log, indicating an RST packet received from google's IP:

Aug 31 11:12:38 svibor kernel: firewall: IN=eth0 OUT= MAC=00:0f:1f:d4:6e:93:00:d0:05:56:a8:00:08:00 SRC=74.125.91.109 DST=129.79.159.99 LEN=40 TOS=0x00 PREC=0x00 TTL=54 ID=11497 PROTO=TCP SPT=993 DPT=55491 WINDOW=0 RES=0x00 RST URGP=0
Aug 31 11:12:38 svibor kernel: firewall: IN=eth0 OUT= MAC=00:0f:1f:d4:6e:93:00:d0:05:56:a8:00:08:00 SRC=74.125.91.109 DST=129.79.159.99 LEN=40 TOS=0x00 PREC=0x00 TTL=54 ID=11498 PROTO=TCP SPT=993 DPT=55491 WINDOW=0 RES=0x00 RST URGP=0
Aug 31 11:42:39 svibor kernel: firewall: IN=eth0 OUT= MAC=00:0f:1f:d4:6e:93:00:d0:05:56:a8:00:08:00 SRC=74.125.113.109 DST=129.79.159.99 LEN=40 TOS=0x00 PREC=0x00 TTL=54 ID=31795 PROTO=TCP SPT=993 DPT=39645 WINDOW=0 RES=0x00 RST URGP=0
Aug 31 11:42:39 svibor kernel: firewall: IN=eth0 OUT= MAC=00:0f:1f:d4:6e:93:00:d0:05:56:a8:00:08:00 SRC=74.125.113.109 DST=129.79.159.99 LEN=40 TOS=0x00 PREC=0x00 TTL=54 ID=31796 PROTO=TCP SPT=993 DPT=39645 WINDOW=0 RES=0x00 RST URGP=0

(please notice frequency and source port 993=imaps) and this continues every 15 min...

whois/nslookup indicate that 74.125.113.109 belongs to google... I am also pretty sure that it is not the external router/firewall problem, because I experience this issue both on my office machine and laptop, from a public wifi/protected wifi/wired connection.

Does this sound familiar to anyone?
Thanks

Last edited by Leonid.I (2010-08-31 16:04:56)

Sin.citadel · 2010-08-31 16:10:28

how many rst reply's do you get per ssl request, are the RST packets causing problems with mail retrieval. try using tcpdump to check the entirety of the conversation between you machine and gmail.

fukawi2 · 2010-08-31 22:56:03

Logging of RST packets are nothing to be concerned about. Part of the connection tracking module being a little over-zealous in detecting 'invalid' packets. Same goes for ACK FIN packets.

Leonid.I · 2010-09-12 16:23:34

Sorry for a delay -- finally got rid of some work... Thanks everyone for the replies.

Well, there are no problems with mail retrieval, nor there are failed conversations.

The same happens also with our university mail servers (not only gmail). Thus I suspect that fetchmail is trying to do something, which makes servers reset the connection. I also asked IT about this, but they have no idea why this is happening...

Last edited by Leonid.I (2010-09-12 16:24:47)

Arch Linux

#1 2010-08-31 16:03:01

Fetchmail, gmail and TCP RST

#2 2010-08-31 16:10:28

Re: Fetchmail, gmail and TCP RST

#3 2010-08-31 22:56:03

Re: Fetchmail, gmail and TCP RST

#4 2010-09-12 16:23:34

Re: Fetchmail, gmail and TCP RST

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