Score:1

Iptables -C (--check) doesn't work

in flag

I have the following Iptables version:

sh# iptables --version
iptables v1.4.21

The help page contains this line:

--check   -C chain      Check for the existence of a rule

I have such a rule in iptables-save:

-A PREROUTING -p udp -m udp --dport 5060 -j CT --helper sip

But when I'm trying to check (-C) it I see such output:

sh# iptables -C PREROUTING -p udp -m udp --dport 5060 -j CT --helper sip
iptables: Bad rule (does a matching rule exist in that chain?).

What is the reason? Could some bug be in Iptables?

Score:2
in flag

Try adding a -t nat so you select the NAT table, or maybe -t mangle. Pretty sure it will default to looking at the filter table, which won't have a PREROUTING chain. You need to specify which table you are looking at.

sh# iptables -C PREROUTING -t nat -p udp -m udp --dport 5060 -j CT --helper sip
A.B avatar
cl flag
A.B
Actually for this one it's `-t raw` (the only one allowing the use of [`-j CT`](https://manpages.debian.org/iptables/iptables-extensions.8#CT))
in flag
Ah, good point. I wasn't paying attention to that.
mangohost

Post an answer

Most people don’t grasp that asking a lot of questions unlocks learning and improves interpersonal bonding. In Alison’s studies, for example, though people could accurately recall how many questions had been asked in their conversations, they didn’t intuit the link between questions and liking. Across four studies, in which participants were engaged in conversations themselves or read transcripts of others’ conversations, people tended not to realize that question asking would influence—or had influenced—the level of amity between the conversationalists.