CentOS 7 Telnet Port Change

DustinB3403

And we're back, dealing with this Yealink Device Management Platform software as I think I have some time to finally begin picking at it again.

Here is what I've done so far on CentOS 7.

I've added a telnet record to /usr/lib/systemd/system/telnet.socket that has:

[Unit]
Description=Telnet Server Activation Socket
Documentation=man:telnetd(8)

[Socket]
ListenStream=9090
Accept=true

[Install]
WantedBy=sockets.target

I've made the port changes with semanage semanage port -a -t telnetd_port_t -p tcp 9090

ValueError: Port tcp/9090 already defined

I've modified /etc/xinetd.conf to read as

# Defining Telnet

service telnet
{
port 9090
}

And still, I'm unable to connect to this system via 9090, I can however connect on the default port (which I did create a port forward rule with this firewall-cmd --zone=public --add-forward-port=port=9090:proto=tcp:toport=23

So what am I missing? Is anyone able to tell me what isn't working here?

FiyaFly

Run

sudo netstat -anp | grep 9090

and it should give you a PID of what is listening on that port. Then run

sudo ps aux | grep <PID>

since it says it's already defined, it's worth checking if something is using it.

EDIT: Sorry replying from a phone and don't remember how to format code on here lol
EDIT 2: had them mixed up. netstat then ps aux

JaredBusch

@dustinb3403 SELinux blocks non-standard ports. You have to allow that there also.

As always, disable for testing unknown things.

DustinB3403

@fiyafly this output nothing netstat -anp | grep 9090

DustinB3403

@jaredbusch said in CentOS 7 Telnet Port Change:

@dustinb3403 SELinux blocks non-standard ports. You have to allow that there also.

As always, disable for testing unknown things.

I just disabled selinux (so it's permissive) and still unable to connect on 9090.

DustinB3403

Gah I'm officially fed up with this software. . . setenforce has port 9090 configured by policy for websm_port_t

black3dynamite

Isn't port 9090 the default port for Cockpit?

JaredBusch

@black3dynamite said in CentOS 7 Telnet Port Change:

Isn't port 9090 the default port for Cockpit?

Yes.

DustinB3403

Cockpit isn't included in CentOS 7 by default (is it?. . . .)

black3dynamite

@dustinb3403 said in CentOS 7 Telnet Port Change:

Cockpit isn't included in CentOS 7 by default (is it?. . . .)

Not with a minimal install. With the problem you are having, I was assuming the issue was with port 9090.