sendmail mystery

[Jonathan Hutchins]

Can't get sendmail to accept connections.  RH7.3, all current patches.

It's not sendmail: removed, reinstalled.  RH has a default DAEMON_OPTIONS
lines that's supposed to prevent connections except from localhost.  Turned
this off.  Verified on another host that turning this on and off indeed
disables/enables connections other than localhost.  With it on, netstat-a
shows the address localhost for the smtp port, with it off it shows a star.

It's not hosts.allow/hosts.deny.  I can get it to generate "tcpwrappers:
connection refused" entries in the log by blocking sendmail in these files,
but with _everything_ unblocked connections are still refused.

It's not firewall rules.  The system is behind a firewall, and if I try
"iptables -L" I get messages about the modules not being loaded.  I conclude
that there is no default firewall on the affected system.

I'm at a loss.  Any suggestions?