In message <200104280431.f3S4VTL00300@xxxxxxxxxxxxxxxx>, Tom Yoksas writes:
> o newer versions of Linux (and FreeBSD) include what looks like all
> registered uses of port numbers in /etc/services. Port 500 (both TCP
> and UDP) is registered to a program called 'isakmp'.
isakmp is the Internet Security Association and Key Management Protocol.
It's in RFC-2408. It's probably not needed right now, but Windows 2000
and the Active Directory support it, along with a growing number of
firewall and VPN products. It seems likely that there will be
conflicts in the future.