[SOLVED] would it be possible to selectively control MTU based on destination subnet?

psycroptic · 09-09-2013, 05:17 PM

so here's my idea: i would like to enable jumbo frames on my local network. as far as i know, if i do that, traffic that exits my network would need to be fragmented, so it's my presumption that if i could control all traffic leaving my client machine and destined to exit the local network and set all of that traffic to 1500 byte MTU, this would not occur. then, the local traffic would still use jumbo frames and internet traffic would not.

is this even possible? it seems logical enough to me...

jefro · 09-09-2013, 11:09 PM

Use two nics?

psycroptic · 09-09-2013, 11:15 PM

eh but then presumably every client would need these, and a few are laptops... ideally i'd like to do it through software on the clients or on the router...

i'm looking into setting the MSS value via iptables, but this wouldn't apply to UDP traffic so...

akiuni · 09-10-2013, 05:11 AM

Hi

I'm afraid but I don't think you can do that even with an alias on the device because the mtu is stored in a single file (/sys/class/net/eth*/mtu) so you can't affect multiples values here.
As far as I can see the only solution would be to use another device, as jefro said.

psycroptic · 09-10-2013, 07:29 PM

word. thanks anyways folks.