I get these from Logwatch's proftpd report (where I have replaced my real server name and IP to the following). Has someone hacked into my server? Should I be worried? :

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my.server.com (M467P017.adsl.highway.telekom.at[62.47.218.81]) - FTP session opened.
my.server.com (M467P017.adsl.highway.telekom.at[62.47.218.81]) - FTP session opened.
12.123.12.123 (M467P017.adsl.highway.telekom.at[62.47.218.81]) - FTP session opened.
12.123.12.123 (M467P017.adsl.highway.telekom.at[62.47.218.81]) - FTP session opened.
my.server.com (M467P017.adsl.highway.telekom.at[62.47.218.81]) - FTP session closed.
my.server.com (M467P017.adsl.highway.telekom.at[62.47.218.81]) - FTP session closed.
12.123.12.123 (M467P017.adsl.highway.telekom.at[62.47.218.81]) - FTP session closed.
12.123.12.123 (M467P017.adsl.highway.telekom.at[62.47.218.81]) - FTP session closed.
12.123.12.123 (M467P017.adsl.highway.telekom.at[62.47.218.81]) - FTP session closed.

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...and these...

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New Users:
mysql(100)
postfix(89)


Connections:
Service imap:
127.0.0.1: 7 Time(s)

**Unmatched Entries**
groupadd[2096]: new group: name=proftpd, gid=500
useradd[2490]: new group: name=mysql, gid=101
groupadd[7982]: new group: name=postdrop, gid=90
groupadd[7983]: new group: name=postfix, gid=89
useradd[7985]: add `postfix' to group `mail'
useradd[7985]: add `postfix' to shadow group `mail'
usermod[13156]: change user `mailman' GID from `32002' to `32002'

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