Finally I fixed it. The TCP windows scaling was broken by the routing layer of my internet modem. I created a new virtual interfaces on my server on the same subnet of the private link of my internet modem to bypass the routing layer and it works well.
Thank you for your help xavier Le 18 juin 2011 à 02:26, Victor Duchovni a écrit : > On Sat, Jun 18, 2011 at 01:30:21AM +0200, Xavier Ambrosioni wrote: > >> 22:16:25.978773 IP smtp10.smtpout.orange.fr.41183 > passrlminisrv.cinema-voiron.fr.smtp: Flags [S], seq 105066692, win 5840, options [mss 1380,sackOK,TS val 2993558281 ecr 0,nop,wscale 8], length 0 >> 22:16:28.978262 IP smtp10.smtpout.orange.fr.41183 > passrlminisrv.cinema-voiron.fr.smtp: Flags [S], seq 105066692, win 5840, options [mss 1380,sackOK,TS val 2993561281 ecr 0,nop,wscale 8], length 0 >> 22:16:34.977258 IP smtp10.smtpout.orange.fr.41183 > passrlminisrv.cinema-voiron.fr.smtp: Flags [S], seq 105066692, win 5840, options [mss 1380,sackOK,TS val 2993567281 ecr 0,nop,wscale 8], length 0 >> 22:16:41.011109 IP passrlminisrv.cinema-voiron.fr.smtp > smtp10.smtpout.orange.fr.41183: Flags [S.], seq 1934215990, ack 105066693, win 65535, options [mss 1460,nop,wscale 1,nop,nop,TS val 537443811 ecr2993567281,sackOK,eol], length 0 >> 22:16:41.051125 IP smtp10.smtpout.orange.fr.41183 > passrlminisrv.cinema-voiron.fr.smtp: Flags [R], seq 105066693, win 0, length 0 >> >> Any idea of the root cause? Could it be an issue with my DNS configuration or is it related with my own smtp server? > > Here's a nickel kid, buy yourself a real firewall. > > More seriously, your firewall does not understand window scaling. Disable > it on your Linux system (see the list archiving for the many previous > instances). Then consider getting a firewall that works with modern > TCP stacks. > > -- > Viktor.
