Domain Name Service:
DNS in Java has been done already.  See <a href="http://sourceforge.net/projects/dnsjava/">
http://sourceforge.net/projects/dnsjava/</a>.  This is LGPL licensed software so could not
be hosted by Apache if a port were undertaken.  It might be best to start afresh as there are
so many possibilities for abstractions and configurable concepts (forwarding DNS impls, DNSlet,
Some using persistence stores, some using databases

Network Time Daemon:
The service that Internet based computers use to synchronise their clocks.  Very useful
for secure and time critical services.

Secure Shell (SSH):
A Heavy crypto mechanism to provide secure access to a remote client.
See <a href="http://www.openssh.org/java.html">http://www.openssh.org/java.html</a>
for details about available java tools.  Mindterm, listed there, would be a good
candidate, but it forked and went in two directions (1) Commercial/closed (2)
GPL.  The latter is not allowed to import ASF licensed code ("Block" being an example)
so could not be ported.  A from scratch impl would be best here.

CIFS/Samba Server:
See <a href="http://jcifs.samba.org/">http://jcifs.samba.org/</a>.
This is LGPL licensed so could be ported to Avalon, but not hosted at Apache.