iptables –uid-owner , how to discover this ID?

postcd · 01-11-2020, 12:21 PM

Hello,

a general question. If iptables manual page (man iptables) shows –uid-owner parameter:

Quote:

–uid-owner { USERNAME } : Matches if the packet was created by a process with the given effective USERNAME

How do i discover this UID?

I tried "id -u debian-tor", it shows an ID. I also tried third string/column from the "grep debian-tor /etc/group" output.

Which one is correct or if none, is there any command that returns the ID?

Or i am totally wrong and the parameter expect debian-tor instead of some number? (even if that is so, it may be interesting for some on how to discover ID behind the username)

jsbjsb001 · 01-11-2020, 12:30 PM

Quote:

Originally Posted by postcd

Hello,

a general question. If iptables manual page (man iptables) shows –uid-owner parameter:

How do i discover this UID?

I tried "id -u debian-tor", it shows an ID. I also tried third string/column from the "grep debian-tor /etc/group" output.

Which one is correct or if none, is there any command that returns the ID?

Or i am totally wrong and the parameter expect debian-tor instead of some number? (even if that is so, it may be interesting for some on how to discover ID behind the username)

/etc/passwd for one, the same command you posted, if you're talking about getting a UID for a user.

You could also do a Google search too...

scasey · 01-11-2020, 12:40 PM

Quote:

–uid-owner { USERNAME } : Matches if the packet was created by a process with the given effective USERNAME

Emphasis added. The parameter wants a USERNAME, not a UID.
The first column returned by

Code:

ps aux

is the USERNAME running the process.

TB0ne · 01-11-2020, 03:42 PM

Quote:

Originally Posted by postcd

Hello,
a general question. If iptables manual page (man iptables) shows –uid-owner parameter:

Code:

–uid-owner { USERNAME } : Matches if the packet was created by a process with the given effective USERNAME

How do i discover this UID?

I tried "id -u debian-tor", it shows an ID. I also tried third string/column from the "grep debian-tor /etc/group" output. Which one is correct or if none, is there any command that returns the ID?

Or i am totally wrong and the parameter expect debian-tor instead of some number? (even if that is so, it may be interesting for some on how to discover ID behind the username)

After working with iptables for **SIX YEARS** now, why can you not apply what you've been told/learned to make any progress on your own? It took you longer to log in here and post a question, than it would have taken you to TRY IT, and see what happened and if it worked.

You AGAIN show no effort into looking up a solution, since just putting "linux iptables uid-owner example" into Google pulls up over 96,000 hits, with samples and explanations. VERY FIRST HIT:
https://www.linuxjournal.com/article/6091

Samples; examples; explanations, showing how both a match and non-match can be used. Why are you not able to do these things, despite being asked so many times? Or put "how to find UID in linux" into Google?