DHCP Servers

BlueToast

I am trying to figure out which servers on the network are acting as DHCP servers. Then I would like to stop them from being DHCP servers and have the pfSense server be the DHCP server. All the servers run Linux (Debian I think), and are of course outdated versions. Please help me to do this. What is the first thing I should do and how?

EDIT: Nevermind, found out by doing pgrep dhcpd on all the servers via SSH.

saqman2060

Great that you found the solution. Keep us posted if you any other issues.

saqman2060

Is it possible to write a tutorial about how you can find dhcp servers on your network? Will help users who encounter the same issue.

mfillpot

I told him the answer in private, the solution is to scan the entire network with nmap, nmap will display all services that are being run on each host.

blue_raptor

whenever a broadcast packet is sent by a box request for an IP, a DHCP server a resonse acknowledging the request. Any packet sniffing tool like tcpdump or wireshark can capture those packets and report about them. So if u could write a script to chk those we hav a monitoring script in place to find unsolicited DHCP servers in your network...