[Udpcast] Spanning Tree/udhcpc failure

Dax Kelson dkelson at gurulabs.com
Tue Nov 4 16:19:05 CET 2008

The portfast setting tunes Spanning Tree timers on Cisco switches. 

Without portfast you get the standard (slow) timers.

Not all switches are Cisco, not all switches have a portfast like setting, not all environments have policies that allow changing the spanning tree timers.

-----Original Message-----
From: Stefan Jäckel <stefan.jaeckel at wiwi.uni-halle.de>
Sent: Tuesday, November 04, 2008 1:25 AM
To: udpcast at udpcast.linux.lu
Subject: Re: [Udpcast] Spanning Tree/udhcpc failure


Am Montag 03 November 2008 20:14:03 schrieb Dax Kelson:
> Hello,
> Can UDPcast be configured to "try harder/longer" to obtain a DHCP lease?
> We have spanning tree running on our switches and updcast always fails
> to obtain a lease on the first three attempts, then manually telling it
> to try again always results in success. This defeats the "preconfigured"
> setup.
> Looking at the docs for udhcpc, I see:
> -T,--timeout=N          Try to get a lease for N seconds (default 3)
> Could you bump this up by default to say 10 seconds (or have it tunable
> on the cast-o-matic)?
I do not think, that the Spanning Tree Protocol is the reason. Maybe 
the "Portfast" setting on the Switch? The Port for the dhcp-connection (at 
boot time, without portfast) is to slow (port on the switch is not up, while 
asking for the lease).
(sorry for my english)


S. Jäckel

> Thanks,
> Dax Kelson
> Guru Labs
> BTW, the mailman page for this list is giving a "500 Internal Server
> Error".
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> Udpcast at udpcast.linux.lu
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