jlivie firewall script

Posted on 2004-08-31
Last Modified: 2010-04-22
hi you gave me a script a while back and i was wondering where i put my ip address for the line below from file call ./iptables-gw

# Uncomment the following  if the inside machines are trustworthy and
# there are services on the firewall, like DNS, web, etc., that they need to
# access. And remember to change the  IP to be that of the INSIDE interface
# of the firewall.

at the moment i only what one LOCAL PC to login via SSH on the internal LAN is this done in the script or SSHD_CONFIG file
Question by:jaxxman
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LVL 40

Expert Comment

ID: 11948989
INSIDE_IP is defined near the top of the file after the initial comment block.

If you only want a single IP on the inside to be able to use ssh you could use:

$IPT -A INPUT -i $INSIDE -s ssh-machine-ip -d $INSIDE_IP -p tcp --dport 22 -j ACCEPT

instead of allowing any machine on the inside to connect on any protocol, which is what the line in the question above does.

Author Comment

ID: 12031906
Sorry its took so long for me to get back i am a bit confussed this bit in the line
Is this the IP address of the PC which is going to connect to the SSH machine
or is this the PC with SSH on it.
by the way i am using SSH to connect to the firewall

Could you please remind me on something.
the iptables-gw file, i edit this file then run it and it updates my iptables. could you please tell me how the system knows that when i execute ./iptables-gw how does it know to update iptables
LVL 40

Accepted Solution

jlevie earned 50 total points
ID: 12031986
"-s ssh-machine-ip" would be the IP of the inside machine that will initiate the ssh connection.

> could you please tell me how the system knows that when i execute ./iptables-gw how does it know to update iptables

When you execute ./iptables-gw it will remove all existing iptables rules and set then back up again.

Author Comment

ID: 12032100
if i renamed iptables-gw will it still work.

still a bit confussed about SSH

the inside ip address of the firewall is and this is the PC which i want to connect to which is running SSH
my windoes PC ip is
so in the script i would use this one
LVL 40

Expert Comment

ID: 12032282
You'd set:


in the script and add:

$IPT -A INPUT -i $INSIDE -s -d $INSIDE_IP -p tcp --dport 22 -j ACCEPT

to iptables-gw. After running the script you'd be able to go to the windows box at , start putty or some other ssh clinet and connect via ssh to your Linux firewall.

And no it doesn't matter what the name of the script file is. You could name it /root/have-a-nice-day and then execute it as ./have-a-nice-day from root's login.
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Author Comment

ID: 12034775
just as a matter of interest is that your picture the one with the woman with sun glasses on. because its a really cool pic of you.
LVL 40

Expert Comment

ID: 12039142
No, that's a made image of a non-existant person.

Author Comment

ID: 12039328
oh sorry, now i am lost as to what you look like but that not important as you are able to answer all my problems.

LVL 40

Expert Comment

ID: 12039383
I really need to get a picture and turn it in...

Author Comment

ID: 12039409
yes that would be a good idea

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