strange connections to imap?

[Erik Steffl <steffl@bigfoot.com>]

  any ideas where do these messages come from?

May 24 02:04:00 localhost imapd[26751]: connect from localhost
May 24 02:04:00 localhost imapd[26751]: imap service init from 127.0.0.1
May 24 02:04:00 localhost PAM_unix[26751]: authentication failure;
(uid=0) -> erik for imap service
May 24 02:04:02 localhost imapd[26751]: Login failure user=erik
host=localhost [127.0.0.1]
May 24 02:04:05 localhost imapd[26751]: Command stream end of file,
while reading line user=erik host=localhost [127.0.0.1]

  I use netscape to connect to imap server running on my machine, it
looks like it's working correctly, at least I can read email with
netscape, I see the mailboxes, new email etc... what causes the messages
above? They appear regularly (not sure since when, I just noticed them
today).

  TIA

	erik