Not able to raise the MTU on FreeBSD 10.3

[Freddie Cash]

On Wed, May 4, 2016 at 12:45 PM, Eugene Grosbein <eugen at grosbein.net> wrote:

> 05.05.2016 2:33, Wayne H пишет:
>
>> I have two new servers connected together with  10 gig Intel and  1 gig
>> Nic cards. It doesn't matter if I have them connected via a switch or
>> directly connected to each other. I am unable to pass ping packets above
>> 1472. If I set the MTU to anything up to 9000 I till can't pass anything
>> above 1472. I have the 10 gig connected via an Intel SFP+ Cable between the
>> servers. I also tried connecting the 1 gig Nics between the servers.
>>
>> I would like to use jumbo frames to mount these servers to a NFS server.
>> If I set the MTU to 9000 in rc.conf on boot up I can mount the NFS but as
>> soon as I try to write to it the NFS hangs. If I umount and reset the MTU
>> to 1500 it works fine.
>>
>> Anyone know what I am doing wrong?
>>
>
> First increase MTU, then assign IP address.
> Or delete it and reassign after increase of MTU to recreate "interface
> route" having its own MTU
> inherited by interface MTU. This MTU of the "interface route" limits you
> and it is not changed
> automatically with interface MTU in your version of FreeBSD.
>

​You can also manually delete and re-add the route with the -mtu option, if
you don't want to drop/add the IP.​


-- 
Freddie Cash
fjwcash at gmail.com