[krbdev.mit.edu #8530] krb5- 1.15 KDC network performance issue

[Greg Hudson via RT]

> Based on a preliminary analysis of net-server.c, it seems that perhaps
>    pktinfo should always be enabled on UDP sockets. It looks like it
>    never causes a failure (at most a warning) and can only help. For
>    instance, if you bind to 127.0.0.1 but the interface is defined as
>    /8, it should still be able to respond even if a packet comes in
>    via 127.1.2.3.

Does that work?  I wasn't aware that you could receive packets at 
multiple addresses except by binding to the wildcard address.

Regardless, setting pktinfo on all UDP sockets is probably the simplest 
solution to that half of the problem.  I'm not sure if we want to log 
the pktinfo-not-supported message for all addresses, though.