Monitoring udp ports

[simerix]

It is possible monitoring udp ports like 162 or 50001 with simple check or another method?

thanks

[limo]

This is quite impossible. UDP is not reliable.. Port can be open and you will never get answer. I think that simple chance how to monitor some udp ports is to check service on it, not availability... When you know what should be on port, you can expect some results.

[James Wells]

Greetings,

Yes and no. By default Zabbix cannot do this, however, there are a couple of ways to go about this;

1. Server Side Scripting -- By using the patch that Sarek created to do external checks, you can execute scripts locally on the server. What you would do is create a script on the server that would perform a UDP port check against the client system.
2. System.Run / UserParam -- Similar to #1 above, but this has a couple of other advantages, such as performing a netstat prior to checking, to ensure the application is running and listening. This script would then run on the client (Zabbix Agent) and send the results to the server.
3. Using a wrapper around fping -- This is actually my preferred method. What you would do is replace fping with a wrapper script that calls one of the millions of udpping packages out there. By going this route, you retain the functionality of fping, but also gain the added capability of testing UDP as well.

[limo]

Yes, of course.

I did not say this is not possible. And fping is probably good solution for it. But in most situations not reliable.. If UDP port seems closed, it does not mean it is closed. Answer depends on data inside "ping" packet.

Small example. If I will send some packet into radius server, it can be configured to send access-reject or simply not answer, depending on request..

[tronite]

This is quite impossible. UDP is not reliable.. Port can be open and you will never get answer. I think that simple chance how to monitor some udp ports is to check service on it, not availability... When you know what should be on port, you can expect some results.

Well this pretty much looks to me like you clearly said it is impossible!

[limo]

Well this pretty much looks to me like you clearly said it is impossible!

In fact, it is possible if you know what you should put into packet....