Max MTU when masquerading a LAN over a modem

zakalwe · Post by **zakalwe** » Thu Apr 27, 2000 6:34 am

Hi,

I have a LAN at home which I masquerade over a dial-up connection, using a linux box. I am using an MTU of 1500 for the LAN. When the linux box masquerades my packets, will it also change the MTU to 576 for them or will they be sent fragmented (does that even work?)?

So basically, should I change the LAN to using an MTU of 576 so that the packets will fit the dial-up connection, or is this taken care of by the linux box?

Thanks,

zakalwe

Noir Pouvoir · Post by **Noir Pouvoir** » Sun May 07, 2000 10:13 pm

Your internal lan should be set to a max MTU of 1500 and set your modem to whatever you find better 576 or whatever there will be no fragmented packets..I,ll assume you know what files to edit..

bdog · Post by **bdog** » Wed May 10, 2000 2:19 am

Add this line to your ipchains script to have your linux box reassemble packets before transmitting them for you.

echo 1 > /proc/sys/net/ipv4/ip_always_defrag