How can I find out IP adresses of DHCP clients when I setup internet connection sharing with Network Manager (Linux)?

Question

I sometimes configure routers with my laptop and use connection sharing with Network manager and so my laptop acts as DHCP server. I then need to connect (via ssh usually) to the servers that are DHCP clients. Is there a simple way to find out the adresses they leased?

Solution

You can check your DHCP lease file (in the case of dhcp isc server /var/lib/dhcp/dhcpd.leases ), the DHCP log, or the Network Manager log (depending the distribution could be /var/log/syslog, /var/log/NetworkManager*, etc.).

The format of these leases could be in the form of:

lease 192.168.42.1 {
starts 0 2000/01/30 08:02:54;
ends 5 2000/02/04 08:02:54;
hardware ethernet
   00:50:04:53:D5:57;
uid 01:00:50:04:53:D5:57;
client-hostname "PC0097";
}

Of course, this may vary the implementation, but any ISC DHCP based implementation should be like this.

Comments

[Marc Torrellas Socastro]

Hm, I am on Ubuntu. Networkmanager log indeed goes to /var/log/syslog but I cannot find the leases there. I found /var/lib/misc/dnsmasq.leases that works though. Thanks for the pointer!