IPTABLES trap

mchitrakar · 11-12-2004, 11:32 AM

dear buddies,

Well I have here a configured Iptables...but now I added 2 new lines
to this table by : "iptables -t nat...." and this has created a problemo..
guys,, is there a way to restore my previous configuration...and what shud i do so that i dont redo such mistakes..i.e do i know to create a backup of iptables before tweaking??? if yes, then please illuminate me how??

Boby · 11-12-2004, 12:01 PM

Hi!

I'm not that big guru in security and iptables. When I wrote my firewall, I created a file called "firewall.sh" and wrote there all iptables commands. Then I run the script ./firewall.sh and it writes everything for me. To make changes, I edit the file and run it again, so I don't have to write everything again.

Boby

mchitrakar · 11-15-2004, 11:48 AM

oh..thanks....i wish i had done the same...can i now remove my previous lines...by re-writing the correct lines..in firewall.sh...that is...will new entry remove my previous entries....???

Boby · 11-15-2004, 05:29 PM

Put this code at the beginning:

Code:

iptables --flush
iptables --table nat --flush
iptables --delete-chain
iptables --table nat --delete-chain

This will delete your previous firewall.

On each run of the script it will delete the old one and build a fresh one.

Hope this helpes!
Boby

mchitrakar · 11-17-2004, 04:01 AM

dear pal,

thnks, but i was wondering if only last 2 entries can be removed...and keeping the old lines before that intact. By the way..how to read the entries in this table?? pls. do reply.

geniarse · 11-17-2004, 05:50 AM

This is possible, first find the rule numbers for the 2 entries you want to delete. do this with:

Code:

iptables -L

count the line number of the 2 rules, this is there rule number, easy

Now delete them with:

Code:

iptables -D nat 7

where natis the table anme and 7 is the rule number.