Looking at my PPPoE server and notice the MTU verys accross the active connections.

I see this when looking at the output of:

int pppoe-server print det
and
int print

Most are all 1480, but some others are, 1476, 1466, 1454

What is the reason for this and why is the apparent default 1480 instead of 1492?

As a side note, this pppoe implementation is in an ethernet network and no ATM.

Thanks!
Dan-

1480 is just default safe value. If you are absolutely sure that 1500 byte packets are forwarded without any problems then you can easily set pppoe mtu to 1492

Alright, I have done so and have had good luck so far.

What about the connections that dont take the default value, what causes this to happen?

Example:
I connected a device that was hard set to 1492, mikrotik was set to 1492 and the pppoe-interface on the mikrotik shows 1488 for that connection.

Thanks!

-dan

PPPoE client can also specify max-mtu and max-mru. For example if client have set 1476 then this mtu will be used instead of server's default value.