Setting MTU size for ppp0
This perhaps needs a little more in-depth knowledge:
I am trying to limit MTU size on ppp0 to below 1492 (that is, I want 1412) because my (new) linux machine has
to masquerade for my roommate (winXP home). I set up pppoe with pppoeconf which configures MTU for ppp0 to 1492.
I did manage to set up masquerading:
#iptables -t nat -A POSTROUTING -j MASQUERADE
#echo 1 > /proc/sys/net/ipv4/ip_forward
Masquerading works fine.
No other rules configured in no other tables and/or chains.
(I haven´t secured this setup yet, so no other rules present.)
PROBLEM IS: my attempts to limit MTU to 1412 are ignored.
tried adding "mtu 1412" to
/etc/ppp/peers/dsl-provider
/etc/ppp/options
still, after reboot or after poff -> ifdown -> ifup -> pon dsl-provider, ifconfig always reports ppp0 with
MTU: 1492. Also tried #pppd noauth mtu 1412 while ppp0 is already active, no effect.
Is some other script overriding my attempts ?
The reason I want to limit MTU is also a special one. My rommmate gets access to every page, EXCEPT ebay!, and
I (randomly) guess this to be connected with MTU size. If I am wrong I will have to dig for some other reason,
but this is another problem to be solved later.
Anybody any clue why setting MTU is ignored ??
Thanks for the help !
PS: I am a newbie, although sitting at my machine 24/7 the last two weeks did help a little to dig into my new
wunderful linux :-) . BTW, using Ubuntu AMD64 (in native 64bit-mode) with self-compiled 2.6.x kernel.
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