can anyone help passing on documentation about the mb_tab ?

I couldn't find anything about it in the online manual pages.
It appears to be related in some ways to networking as all
TCP/IP response from a hosts stoped when an error occured
on the console stating that the mb_tab was full.

I'd like to try and work out what caused it to fill up and
make some changes to the installation so it can cope in future.

I guess its diffined somewhere in the kernal nad maybe rebuilding
a news kernal with a larger table will resolve the problem.

Can anyone give me their thoughts on the problem ?

--Sean