Can't open port in firewalld

[T.C. Hollingsworth]

On Sat, May 18, 2013 at 1:47 PM, আনন্দ কুমার সমাদ্দার
<ananda at samaddar.co.uk> wrote:
> Hello all,
>
> So I've found out that by default my script controlled ethernet
> connection is in the public zone in firewalld.  I however cannot open a
> port for Transmission, the torrent client.  I set Transmission to use
> the static default port 51413.
>
> I then do the following:
>
> firewall-cmd --zone=public --permanent --add-port=51413/tcp
> firewall-cmd --zone=public --permanent --add-port=51413/udp
>
> Transmission shows the port as closed.  It's definitely a firewalld
> issue.  As soon as I disable firewalld by using systemd the port is
> shown as open in Transmission.
>
> Am I doing something wrong here?

Well, if you use `--permanent` the setting won't take effect until
after firewalld (or your computer) is restarted, but starting and
stopping firewalld like you did to test it should have taken care of
that.  (You can call `firewall-cmd` without `--permanent` to get the
settings to take effect immediately.)

Do you have a router in between your machine?  You might need to
open/forward the port in that too.

Otherwise, transmission-gtk might be lying about the port being open.
(I've been using Deluge instead of Transmission for what seems like
ages now, but I do recall the port open checking thingy in
Transmission not working so good before.)  Try checking the port with
`nmap` or ShieldsUP [1] and see if that reports it as open.

-T.C.

[1] https://www.grc.com/x/ne.dll?bh0bkyd2