ログ(/var/log/messages)を見てみると、

[code]
Sep 19 14:35:32 ns inetd[9493]: warning: /etc/hosts.allow, line 38: can't verify
hostname: getaddrinfo(aaa-bbb-ccc-ddd-nsw-static.tpgi.com.au, AF_INET) failed
Sep 19 14:35:52 ns inetd[9493]: refused connection from aaa.bbb.ccc.ddd, service i
pop3d (tcp)
[/code]

とpopが拒否されてます。

/etc/hosts.allowのline38は”PARANOID”です。

[code]
# Protect against simple DNS spoofing attacks by checking that the
# forward and reverse records for the remote host match. If a mismatch
# occurs, access is denied, and any positive ident response within
# 20 seconds is logged. No protection is afforded against DNS poisoning,
# IP spoofing or more complicated attacks. Hosts with no reverse DNS
# pass this rule.
ALL : PARANOID : RFC931 20 : deny
[/code]

どうやら、自宅のADSLのIPアドレスが逆引きできなくなっているのが原因のようです。

“ALL : PARANOID : RFC931 20 : deny”の設定をコメントアウトしてとりあえず解決。