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SofaKng
Asked: 2011-08-29 06:16:38 +0800 CST

Dell PowerConnect 2824 - DHCP takes 30 - 40 seconds to respond

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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?

dhcp dell-powerconnect

2 Answers

  1. Best Answer

    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/

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  2. 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

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