3

I have a very strange problem. DHCP requests (to my router, going through my PowerConnect switch) take 35 - 40 seconds.

Here is my setup:

Router (pfSense) --> PowerConnect 2824 switch --> LAN

DHCP server is disabled on the PowerConnect 2824 but is enabled on my router. However, any requests on my LAN take 30 - 40 seconds to receive a DHCP response.

I've tried a different switch (Netgear Prosafe) and it works perfectly and I receive an instant DHCP response so I know the problem is not with my router.

Can anybody please help me out?

SofaKng
  • 401

2 Answers2

7

It's probably got nothing to do with DHCP. It's probably spanning tree. The switch is simply unwilling to enable the port until it confirms that the port will not cause a disastrous loop in the network. The solution, assuming you know that the port will never, ever form a loop is to enable portfast (or 'fast link'). See this link:

http://www.mcbsys.com/techblog/2010/02/gigabit-switch-spanning-tree-causes-slow-logon/

David Schwartz
  • 31,893
3

It's spanning tree. It's enabled by default on Dell switches. You can turn on portfast like this:

interface range ethernet e1-24
spanning-tree portfast

Jason Berg
  • 19,334