Hi!,

In one sendmail server i always see some mails with unknown usernames.

When i grep the maillog i get the following result;

[root@mail log]# grep m0N7xwqc003714 maillog
Jan 23 13:30:03 mail sendmail[3714]: m0N7xwqc003714: <garyw@*****.com>... User unknown
Jan 23 13:30:05 mail sendmail[3714]: m0N7xwqc003714: from=<>, size=4007, class=0, nrcpts=0, proto=ESMTP, daemon=MTA, relay=mailcleaner.******.com [10.10.10.150].

Send mail server is configured to relay mails only from 10.10.10.x range.

I like to know why theses comes with from=<>

Thanks in advance.

Spammers like to take a domain name and guess at actual usernames or email addresses in hopes it reaches a human. Ignore them and move on, nothing really to worry about.