I also get:

Mar 1 07:50:58 ns sshd[4492]: Failed password for invalid user Admin from

::ffff:218.xx.xx.xx port 63778 ssh2
Mar 1 07:50:58 ns sshd[4493]: Failed password for invalid user user1 from

::ffff:218.xx.xx.xx port 64844 ssh2
Mar 1 07:50:58 ns sshd[4500]: Invalid user na from ::ffff:218.xx.xxx.xx

and from many other IP

I checket netstat -p and seems clean !

can u help me with advices ?

The log entry's you are seeing are just log in attempts. There are lots of scripts scanning for open ssh ports and trying some username/password combinations to get access to systems.
I guess it is easiest to only allow ssh access from ip addressess you connect from and block traffic to port 22 from every other ip in your iptables firewall.
You can also change your sshd_config to set a maximum number of login attempts with the option "MaxAuthTries 3", probably there is already a default of 6.

So i verified MaxAuthTries in sshd-config and it was commented with #, so that's why i got so many tries to break user/pass in var/log/secure.

My server was configured in 2004 last time by some friend, with fedora core 3, and is up and now.
I am a beginner in linux sistems, i would be interested to allow connection on SSH only to 1 or 2 ip local or from WAN.

Would u be kind to help me with these set up ?

Also i want to block/add some of those ip who attack my server to actual firewall (iptable) to ignore them from now on.

Thank you.

@pk21: it says RH 9 on your profile
@icoman: are you really running Fedora 3

In both cases, those OSes have not been updated in years and are wide open to exploits.
You really need to get current: Fedora is at v18 or 19 I believe.
The old RH series ended on v9. I recommend going for Centos 6.3 ( a free version of RHEL)

https://en.wikipedia.org/wiki/Fedora...ting_system%29
https://en.wikipedia.org/wiki/Red_Hat_Linux
https://en.wikipedia.org/wiki/Red_Hat_Enterprise_Linux
https://en.wikipedia.org/wiki/CentOS

icoman
and running the long dead fedora 3 or 4 ,You will have problems .
install fedora 18 first
then see

but for a server
fedora is really the very LAST thing that should be installed on it

Using a long life distro like the current CentOS 6.3 would be best , if you stay in the red hat family

I already installed CENTOS on separate HDD .. for testing purpose BUT CAN'T configure to match old server config, i mean to keep online 3 website and 7 email clients.
Mostly i don't or cant configure the apache to see those 3 site.
The user email i created but that's all that works ..
CentOS come with apache installed but cant config that .. and i reinstalled and then was up and runnig but for 1 site only...

If there is other linux distro better for server please recommend one and link for tutorial install - configuration.

without being able to read your "httpd.conf" file and any ".htacces " files
i can only guess

the 3 are using a virtual host
if the httpd.conf file is still the DEFAULT ( but edited) file
90% of it is instructions on setting it up
BUT here is the BIG problem
fedora3 had i think Apache2.2
Centos6 has Apache2.4
there is a very big difference in the two
see the apache documentation
http://httpd.apache.org/
2.2
http://httpd.apache.org/docs/2.2/
and 2.4
http://httpd.apache.org/docs/2.4/

the apache 2.4 virtual host section
http://httpd.apache.org/docs/2.4/vhosts/

for running a server the three best are
--- place in ANY order ! all 3 are about the same ---
RHEL- current
Debian stable
Slackware

thank you. i will install new linux debian i think ... or centos these friday.