>> > A while back I was having networking issues.  I eventually tried
>> > drastically lowering the MTU of all the systems onsite and the issues
>> > disappeared.  I always thought the issue was due to the MTU on our
>> > modem/router.  Today I read that AT&T DSL requires a 1492 MTU so I
>> > increased the MTU of our systems up to 1492 and haven't had any
>> > issues.  Do certain ISPs require you to change the MTU of your entire
>> > network, or is this likely due to our AT&T modem/router itself?
>> AFAIK the MTU is defined for every network interface separately. For an
>> ADSL connection it is common that a lower MTU is needed because of the
>> PPPoE header information that is encapsulated in the ethernet frames.
>> But in that case it is sufficient to lower the MTU just for the WAN
>> interface that is connected to the DSL modem.
>> If you don't use protocol encapsulation in your LAN then there should
>> be IMHO no reason for lowering the MTU of your internal interfaces.
>> --
>> Regards
>> wabe
> MTU is per network interface but you really don't want to end up having
> your router fragment every IP packet because systems on your subnet are
> using a larger MTU.
> Todd

That makes sense.  So in my case, I'm thinking 1492 MTU on every
interface in the network.

So I'm sure I understand, should everyone with a DSL connection set an
MTU of 1492 (or potentially lower) on all of their network interfaces
to avoid packet fragmentation?

- Grant

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