LinuxQuestions.org - pppoe MTU fedora core2

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pppoe MTU fedora core2

I'll give some quick background.

DSL pppoe modem -> netgear 4 port switch -> Netscreen 5GT & FC2 NAT box

NAT box: FC2
dual 2000+ athlon w1GB RAM, 2NICs being used.

LAN:
netgear 4 port switch, Aopen 8 port switch, linksys WiFi 802.11b AP

I get crap speed out (12-33 kBps --- to 0 after a while on most sites) of any machine connected through the FC2 nat box. I think that it is MTU/MRU related, so i add the following options to /etc/ppp/options:

Code:

mru 1452

mtu 1452

reconnect... ifdown ifcfg-ppp0; sleep 3; ifup ifcfg-ppp0

but when i check the process... mru mtu still set to 1492?

Code:

root    16803 16770  0 14:44 ?        00:00:00 /usr/sbin/pppd pty /usr/sbin/pppoe -p 

/var/run/pppoe-adsl.pid.pppoe -I eth1 -T 80 -U  -m 1412    ipparam sympatico_ca 

linkname ppp0 noipdefault noauth default-asyncmap defaultroute hide-password 

nodetach usepeerdns mtu 1492 mru 1492 noaccomp noccp nobsdcomp nodeflate 

nopcomp novj novjccomp user [usernamedeleted -sb] lcp-echo-interval 20 

lcp-echo-failure 3

then I added MTU=1452, MRU=1452 to /etc/sysconfig/network-scripts/ifcfg-ppp0 but the same effect is seen.

Any ideas?

I'm fresh out...

Seems one of the ports on my Aopen switch is bad. Changed cables to the NAT box LAN side and everything worked normally suddenly. Total red-herring ....

BTW everything I found seems to indicate that 1492 MTU on a pppoe interface is "EXCATLY WHAT YOU WANT" and that is why you can't change it... :-)

CLAMPMSS is what you really want to change. ( in /etc/sysconfig/network-scripts/ifcfg-ppp0 )

and you know someone this morning even said, "Have you checked the cables?" grrrr. frikin' 'wiggle-the-wires' solution... ;(