sendmail: Operation timed out with

[Justin Brody]

Hello,
I've been unable to get sendmail to send mail properly and am hoping
someone can give some advice.  My internet connection is fine; I can use
ssh, http, etc. without any trouble.  My machine connects to a a router
which is connected to a cable modem:

aleph# netstat -r
Routing tables

Internet:
Destination        Gateway            Flags    Refs      Use  Netif Expire
default            192.168.0.1        UGSc        7        0    rl0
localhost          localhost          UH          1       49    lo0
192.168.0          link#1             UC          1        0    rl0
192.168.0.1        00:80:c8:24:0b:cb  UHLW        8        0    rl0    823

aleph# ifconfig rl0
rl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        inet6 fe80::2e0:4cff:fe98:36fa%rl0 prefixlen 64 scopeid 0x1
        inet 192.168.0.197 netmask 0xffffff00 broadcast 192.168.0.255
        ether 00:e0:4c:98:36:fa
        media: Ethernet autoselect (100baseTX <full-duplex>)
        status: active

I can't send any mail though.  The first entries in my mail queue:
i22K75of000208        3 Tue Mar  2 15:07 <justin at aleph.none.org>
                 (Deferred: Operation timed out with math.umd.edu.)
                                         <brody at math.umd.edu>
i22K6mof000198        5 Tue Mar  2 15:06 <justin at aleph.none.org>
                 (Deferred: Operation timed out with math.umd.edu.)
                                         <brody at math.umd.edu>

And lots more like it.  I can telnet to math.umd.edu port 25 just fine.
I've also tried sending to other addresses and using '-f' to set my return
address.  That unfortunately exhausts my knowledge of sendmail!

I'd greatly appreciate any help!  I browsed some on the internet and saw
that someone once had a similar problem with his hostname being set
incorrectly.  I wasn't sure how to look at that though...

Thanks,
Justin Brody