A while back I wrote, about TCP portbinding:

Unfortunately, you can't bind a port to the generic wildcard addressif anyone is using the port on a specific IP address, hence the Apacherestart problem. (Why this port binding limitation is a sensibleis beyond the scope of this margin, but it is, however annoying itperiodically is.)

Today I feel like explaining why. The core problem is deciding whogets handed a new connection (or for UDP, a new packet); if

I used to be a big proponent of getting SMP PClone servers instead ofuniprocessor ones. Nowadays, though, I'm not so sure, and I now activelytilt towards UP machines.

The advantage of SMP over UP is more CPU capacity and to someextent larger caches (if the OS scheduling works out right). ButInternet-facing servers are rarely hurting for more CPU; often youreally want more IO and maybe more memory.

(This assumes that the server is not grotesquely overconfigured to startwith,