>All I know about dns and routing, I learned from the O'Reilly book,
>"TCP/IP and Networking". There is a named.conf(5) man page, but you
>shouldn't have to worry about that. That's for your professor to deal
>with, and it looks like he did! The attached nslookup session shows
>that guy.chonju21.net MX's to chonju21.net. Since you have no reason
>to run your own nameserver, as I do, you would run nslookup by
>
>nslookup - cobalt.tooman.com
>
>(Note the "-".) All you need to do is run sendmail, if you aren't
>already. The default configuration should be fine. We'll find out when
>I send this email!

Why would you want to do nslookup - cobalt.tooman.com? I don't run any DNS
on my machine, & I do nslookups just fine without the "-". As long as you
have a valid resolv.conf, your machine knows everything it needs to for
doing lookups.

As for "all you need to do is run sendmail", what he was referring to is
the fact that MX records allow you to set priority of one host over
another. If you look up my ns records, you'd see that each of my domains is
MX'd primarily to my machine, & secondarily to my ISP's mailserver. That
mailserver will hold my mail until I log on, at which time it'll deliver it
to my sendmail. This way, the senders won't get messages "mail
undeliverable for the past four hours" if I happen to take my computer
offline.

Here's what an nslookup on MX records will show for me:

prez# nslookup -query=MX prez.org
Server:  ns1.servtech.com
Address:  199.1.22.2

prez.org        nameserver = ns1.servtech.com
prez.org        nameserver = ns2.servtech.com
prez.org        nameserver = b.ns.verio.net
prez.org
        origin = ns1.servtech.com
        mail addr = dnsadmin.servtech.com
        serial = 1998101001
        refresh = 10800 (3H)
        retry   = 1800 (30M)
        expire  = 1209600 (2W)
        minimum ttl = 43200 (12H)
prez.org        internet address = 204.181.2.103
prez.org        preference = 10, mail exchanger = prez.buf.servtech.com
prez.org        preference = 50, mail exchanger = mx0.ny.verio.net
prez.org        nameserver = ns1.servtech.com
prez.org        nameserver = ns2.servtech.com
prez.org        nameserver = b.ns.verio.net
ns1.servtech.com        internet address = 199.1.22.2
ns2.servtech.com        internet address = 199.1.22.7
b.ns.verio.net  internet address = 129.250.35.32
prez.buf.servtech.com   internet address = 204.181.2.103
mx0.ny.verio.net        internet address = 199.1.22.8
prez#

The line with preference = 10 tells SMTP servers to try first to send
directly to me (prez.org == prez.net == prez.buf.servtech.com). The line
with preference = 50 means that if they can't reach me, they can send it
off to mx0.ny.verio.net and consider it delivered.


Mike
Bikers don't *DO* taglines.