Case: NIM server has been working fine - forever it seems, and then disaster strikes. You cannot install new systems! BOOTP is failing. Running tcpdump on the nim server shows something like this:

 ICMP nim udp port bootps unreachable, length 36

Question: did you recently run aixpert -l high? If so, you are probably having the same problem I had yesterday.

The solution is quite simple: restore bootp and tftp entries in /etc/inetd.conf - aixpert has just disabled them.

Note: just running aixpert -l default does not restore the blocked entries for bootp and/or tftp - at least it did not happen for me.

In short, NIM and client bootp issues - verify /etc/inetd.conf on the nim server.