15 Feb
2002
15 Feb
'02
10:19
When i set up any machine on my network, it picks up an ip number from somewhere, but not from my domain. I assume whatever port dhcp works on is open, allowing it to pick up an ip from an outside dhcp server. Which port/protocol do i block to stop machines picking up this outside DHCP server?
I am not sure whether dhcp is a routable protocol in the first place; if it is not, an outside machine can neither receive nor answer dhcp requests from your machines. AFAIK dhcp clients broadcast their subnet only.
Here you can checkt it out http://www.udel.edu/network/how.html Summary : ethernet broadcasts - if a router on ethernet that knows i dhcp-server outside it will route masked with own ip.