need some help

[Jim Reid]

>>>>> "Hannah" == hoyoung  <hoyoung at us.ibm.com> writes:

    Hannah> A server in the Dept has name :dublin.mayo.rock.edu.  The
    Hannah> owner of the server needs to rename it to:
    Hannah> public.nash.rock.edu.  I'm the admin for domain
    Hannah> mayo.rochester.edu which is in city A.  nash.rochester.edu
    Hannah> is in B city and owned by my counterpart.  The server will
    Hannah> also use an IP belonged to nash.roch.edu.

    Hannah> Can this be done?  I can have it respond with B city's ip
    Hannah> address when someone queried dublin.mayo.rock.edu.  But
    Hannah> that isn't politically correct, is it?  Can I just point
    Hannah> to nash.rochester.edu with a cname or something?  In any
    Hannah> case, the reverse lookup should never give  the Mayo name.
    Hannah> Is this doable? 

There is no reason why you can't enter an A record which has an IP
address that "belongs" to some other domain. It's just an A record
after all. There's nothing in the DNS protocol which confines any
domain to have a certain range of IP addresses. [Well I suppose you
could argue that PTR records and in-addr.arpa domains define a range
of IP addresses, but that's different from what's being discussed
here.] However it's usually not a good idea to do put A records for
other people's IP addresses in your zone file. What if the host gets
renumbered? What if that IP address gets assigned to some other host?
There can also be problems with forward and reverse lookup mismatches,
especially with things like rsh and rcp. You're safer to make the
entry in your zone file a CNAME for the corresponding name in it's
real domain. ie:
	dublin.mayo.rock.edu. IN CNAME public.nash.rock.edu.

or should that be s/rock/rochester/g... ? :-)