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Old 09-17-2003, 03:32 PM   #1
BwiNfon
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Question port blocking


I'm not entirely sure that this is the correct place to post, but it seemed like it so here goes....

I am pretty new to linux in general. I am a network admin in training and i just finished setting up a DNS caching only server on my internal network, which is behind a pretty decent firewall. I would like to block all the ports that i don't need to use on my caching DNS server. Would I use iptables to set this up? I don't want anything complicated. I just want my 'firewall' to say "don't let anything in unless it's on these 6 or 7 ports". thanks.
 
Old 09-17-2003, 03:39 PM   #2
cyph3r7
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hmmmm not sure if I am a fan of putting a firewall on every server. If this machine is behind a firewall you may complicate things more if anyone wants to add say DHCP to this server. Lock it down and disable everything you don't need to be running.

check the stickys above for more info........
 
Old 09-19-2003, 05:48 PM   #3
aqoliveira
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edit /etc/services file and hash out all ports in that file EXCEPT the port you want it to listen on e.g 53 for DNS. use either netstat -a to check all ports that listening and chkconfig --list. Once services and ports have been id then disable them or remove them.

There are other ways of doing this but this should doit

chow
 
Old 09-19-2003, 08:44 PM   #4
Robert0380
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Quote:
Originally posted by cyph3r7
hmmmm not sure if I am a fan of putting a firewall on every server. If this machine is behind a firewall you may complicate things more if anyone wants to add say DHCP to this server. Lock it down and disable everything you don't need to be running.

check the stickys above for more info........
wow, why not put a firewall on every server? if your firewall gets cracked, then that leaves all of your other servers butt naked to an attack. firewall everything is my motto. you never put all your eggs in one basket. if they wanted to add a DHCP server to it, editing a firewall script should be easy if they are capable of adding the server.

this would especially be the case if you have clients on your network behind the firewall with you that belong to Kazaa users.

Last edited by Robert0380; 09-19-2003 at 08:46 PM.
 
Old 09-25-2003, 10:51 AM   #5
BwiNfon
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No kazaa, but my net admin certainly knows how to set up DHCP and how to do any firewalling and/or poking holes in our firewall as is necissary. I don't though....which is why i'm learning anyways, i am still working on this, i'll let you know if i have any more questions.
 
  


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