Linux Firewall Help

[Neo81]

Ok, The situation is that our internal network runs through a firewall into our isp network, it is only a small isp with 6 dial in lines for our clients. The problem is that I would like to have a news port and a telnet port open so as I can join news groups and telnet into clients but cannot do this due to the stringent secruity within the firewalls and the fella who used to look after the ISP and Web Hosting has now left the company, so there is just me who does the sys admin off instructions he had left me. I myself am learning Linux at home in my spare time aswell as at work doing the isp admin, so i know enough to get me by apart from the firewall with only 4 ports open into my internal network. The firewall machine is a sparc 5 station I think which boots up via a boot disk. Is there anyway that I could edit this firewall easily to open a few more ports into this network, ask me more specific questions if you need more info to help out

Thanks
Later
NEo81 >:O>

 

[capitano]

What is the OS? Is it Linux? Do you know if it's using IPchains or IPtables packet filtering firewall?

Bryan

 

[Neo81]

this is what I can gather off the server overview doco. We have 2 firewalls box's one is running IPX Red Hat Linux which is in between the network I am in and the ISP network which only has 5 ports open (http, smpt, ftp, telnet and pop3) and then we have another firewall in between the the our isdn provider and the ISP network which is running INTEL LRP which has many more ports open to the

http://www then

the firewall I am behind

Later
NEo81 >:O>

 

[ifincham]

Hi,

I believe Redhat dropped sparc after 6.2 so its almost certainly an ipchains based firewall you have there. The problem is that it could be a home grown script or a firewall app of some kind which generates the ipchains statements. You would need to work out how the ipchains code is triggered - its probably either called from /etc/rc.d/rc.local script or as part of the sysv init process. If its the latter, you can use chkconfig to see what services are running and then examine the startup script for clues :

# /sbin/chkconfig --list
(scripts are in /etc/rc.d/init.d - e.g. a service called 'ipchains' would have a script /etc/rc.d/init.d/ipchains)

also

# cd /etc/rc.d/init.d
# grep -i ipchains *

.. to find scripts with 'ipchains' inside.

Or it could just be that its was done with ipchains-save and ipchains-restore commands. Something like :

# /sbin/ipchains-save > /etc/ipchains.rules
(saves active rules as listed by '/sbin/ipchains -L')
# /sbin/ipchains-restore < /etc/ipchains.rules
(restores rules saved in file)

To give you an idea of what an ipchains script looks like, an example is here -->

http://www.redhat.com/support/resources/tips/firewall/firewallservice.html

Of course, you can always just add rules at any time from the command line .

Hope this helps

 

[Neo81]

Thanks for your help, I'll have a little play around with it now and see what I can do, if not I shall be back....

Later
NEo81 >:O>