strange things in my /var/log/auth.log

[Stevan Tiefert]

Hello list,

when I do that:

cat /var/log/auth.log | grep listening

I got this:

Mar  3 14:23:21 mail sshd[380]: Server listening on :: port 22.
Mar  3 14:23:21 mail sshd[380]: Server listening on 0.0.0.0 port 22.
Mar  3 17:01:51 mail sshd[2364]: Server listening on :: port 22.
Mar  3 17:01:51 mail sshd[2364]: Server listening on 0.0.0.0 port 22.
Mar  3 17:11:15 mail sshd[406]: Server listening on :: port 22.
Mar  3 17:11:15 mail sshd[406]: Server listening on 0.0.0.0 port 22.
Mar  9 12:51:47 mail sshd[408]: Server listening on :: port 22.
Mar  9 12:51:47 mail sshd[408]: Server listening on 0.0.0.0 port 22.
Mar  9 13:19:28 mail sshd[407]: Server listening on :: port 22.
Mar  9 13:19:28 mail sshd[407]: Server listening on 0.0.0.0 port 22.

These messages are only two times appeared in the last nonstop-run of my 
mashine over one week...
Is this normal, I don't think so? I have to say that somebody tried in the 
last week several times to login per ssh, but didn't had success because I 
have a good password I think...

With regards
Stevan Tiefert