Discovery with telnet port 23

[Darkon91]

Hello community,

I have a discovery check which scans for ICMP Ping and telnet port 23.

Our switches all react on telnet port 23 but some are not displaying a result in the monitoring --> Discovery

Anything I miss in the settings?

Kind regards,
Christian

[Ed.M]

Hello! Can you show your discovery rule and discovery action settings?

[Darkon91]

Hope this is what you need?

Discovery rule 200 Network:

FTP <-- Port range 21
ICMP ping
SNMPv1 agent "1.3.6.1.2.1.1.3.0"
SSH <-- Port range 22
Telnet <-- Port range 23

Action 200 Network

Conditions:
Discovery check equals 200 Network: ICMP ping

Operations:
Add host
Add to host groups: 200 Network
Link to templates: Template Module ICMP Ping
Set host inventory mode: Automatic

Action 200 Network Switch

Conditions:
Discovery check equals 200 Network: Telnet
Host IP equals 10.24.253.1-254

Operations:
Link to templates: Template Net Cisco IOS SNMPv2
Unlink from templates: Template Module ICMP Ping

[Darkon91]

Any update on this?

[mfortes]

Can u post your discovery and iten prototype?
Zabbix are showing any message about this itens?

[Darkon91]

Here we go.

The discovery finds this:


The discovery is attached as file.

The strange thing is that some are found (line 2 and Line 6) but some are not.

Any more details you need?

If I telnet on these devices it works fine by the way.

Thank you.

Regards,
Christian

[Hamardaban]

If I telnet on these devices it works fine by the way.

Are you checking the telnet connection from the same server / proxy that is performing the discovery?

[Darkon91]

Yes, this is from the zabbix proxy where the discovery is running on.

As example I used telnet on one device that does not show telnet as active but as you can see it works.



What I now tried in addition is to connect to one device that works fine and I can see a difference.

On the above you see a different order and it is not asking for a username, only for a password.
The device that works asks for username and password.



Any idea?

Regards and many thanks.
Christian

[Hamardaban]

Discovery uses net.tcp.service functionality....
Here https://www.zabbix.com/documentation..._check_details you can see:
“telnet Creates a TCP connection and expects a login prompt (':' at the end).
=> no login prompt - no telnet detected.

You may use just tcp-on-23-port check...