Hello Jamin, > Not from what I recall, but I could very well be wrong (never really > used PPPoE). I thought, packets originating on the Linux box would obey > the MTU, but packets coming in on other interfaces would have the MTU of > their interface.
You could be right with MTU/MRU. I found "http://www.sauff.com/dsl-faq/mtu-mini-faq.html#1.5"; It's in german language..... They talk of MSS and MSSClamping. Here also GMX is mentioned (ICMP blocking and so no path MTU discovery). A solution of solving the MSS problem on a router system is mentioned: * MTU: setting of MTU/MRU in ppp/option file: [...] mru 1492 mtu 1492 [...] * CLAMP-MSS: (I triy to translate since there is some IPTABLES command which maybe is worth to be integrated into your firewall-script) "The rp-pppoe driver allows via the /etc/ppp/pppoe.conf an option CLAMPMSS=<value>. This file will only be evaluated if pppoe will be started by the included basch-scripts (adsl-*). If these scripts are not used the pppoe-binary must be called with option "-m <value>". Alternatively or with the kernel-driver which don't know such options, MSS-Clamping can be achieved from kernel 2.4 on with following line: usr/sbin/iptables -I FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu With kernel version 2.2 the module mssclampfw has to be loaded. [...] I use the kernel driven pppoe with rp-pppoe as an plugin to pppd so I prefer the iptables thing.... ;-) Only when entering the above command (or adding it to the end of the "masq_networks()" routine) shows an error: "iptables: No chain/target/match by that name" Maybe a missing kernel module?!? I will try finding some more details.... -- CU __ (_ __)tephan Neumeister
