How can I tell which clients are connecting to a NIS/ypserv master server?

Funnily enough, I was doing that just this morning, to verify that people were talking to my new NIS server.

Firstly, find the port that ypserv is on with

oldserver> rpcinfo -p|grep ypserv
    100004    2   udp    844  ypserv
    100004    1   udp    844  ypserv
    100004    2   tcp    847  ypserv
    100004    1   tcp    847  ypserv

Then, you can use tcpdump to look for traffic:

oldserver> sudo tcpdump -n -n port 847 or port 844
[...]
15:09:18.714526 IP 192.168.20.102.707 > 192.168.1.87.844: UDP, length 56
15:09:18.714679 IP 192.168.1.87.844 > 192.168.20.102.707: UDP, length 28
15:09:20.717203 IP 192.168.1.105.900 > 192.168.1.87.844: UDP, length 56
15:09:20.717296 IP 192.168.1.87.844 > 192.168.1.105.900: UDP, length 28
15:09:21.326160 IP 192.168.1.39.719 > 192.168.1.87.844: UDP, length 56
15:09:21.326225 IP 192.168.1.87.844 > 192.168.1.39.719: UDP, length 28

As you can see, my server (192.168.1.87) is definitely getting traffic. If you don't see anything after a half-hour or so, you're not getting anything.

How can I tell which clients are connecting to a NIS/ypserv master server?

Related

Recent Posts