Hello Stephan, Now I solved the problem (although I don't know in detail what I am doing...):
The things I've done now now are: 1.) "firewall.conf" [...] POSTSTART="/etc/ppp/mssclamping" POSTRESTART="/etc/ppp/mssclamping" [...] 2.) creating a script "/etc/ppp/mssclamping": [------------------------] #!/bin/sh IPTABLES=`which iptables` echo -n ": MSS clamping: " $IPTABLES -t nat -I POSTROUTING 1 -p tcp --tcp-flags SYN,RST SYN \ -j TCPMSS --set-mss 1400 $IPTABLES -I FORWARD 1 -p tcp --tcp-flags SYN,RST SYN \ -j TCPMSS --set-mss 1400 [------------------------] Now also SMTP transfer works. I set the MSS-value by hand because the "--clamp-mss-to-pmtu" which was proposed in some articles did not work..... Strange thing; maybe I will download the rp-pppoe package and install these scripts since then the MSS-Clamping should be done internally by pppoe. -- CU __ (_ __)tephan Neumeister