Don't miss the obvious
I've recently replaced my old home router (well, actually a combination of two low-end models, one could handle ISDN and the other one 3DES) with a 1812. After I've struggled past the “interesting” interface names (it has 8 switched ports, named FastEthernet2 to FastEthernet9) and brushed up my BVI/VLAN skills, configuring it was a breeze … only the DHCP server was causing me problems; every time my laptop would wake from the standby mode, it would take almost half a minute before it got the LAN IP address. The obvious suspect (as I've installed the 12.4(15)T on it) was the software, the next one DHCP ping timers.
After replacing the software (didn't help) and tweaking DHCP timers (no change), it finally dawned on me: the ethernet ports are switched, so the spanning tree was playing tricks with me. Disabling spanning tree with the spanning-tree portfast interface configuration command solved the problem.
After replacing the software (didn't help) and tweaking DHCP timers (no change), it finally dawned on me: the ethernet ports are switched, so the spanning tree was playing tricks with me. Disabling spanning tree with the spanning-tree portfast interface configuration command solved the problem.
Linky
- Bill
I have
interface Dot11Radio0
description Wireless
no ip address
no ip redirects
ip accounting access-violations
!
encryption mode ciphers aes-ccm
!
ssid Wireless
!
speed basic-1.0 basic-2.0 basic-5.5
54.0
station-role root
world-mode dot11d country GB indoor
bridge-group 1
bridge-group 1 subscriber-loop-contr
bridge-group 1 spanning-disabled
bridge-group 1 block-unknown-source
no bridge-group 1 source-learning
no bridge-group 1 unicast-flooding
and
spanning-tree portfast bpduguard
and the fa ports are set up by SDM as part of the BVI
but my hosts often fail to get a connection on waking.
What next?!
What I find perplexing is that the DHCP seems ropey both on the Wireless interfaces (although that could be to do with security settings, etc, I suppose) and the LAN interface with a Mac OS X Tiger. Wired Windows machines seem less prone to DHCP failures.
A more complete listing of my setup, before I had added the bpduguard command, is at http://www.dslreports.com/forum/remark,18550344
Suggestions for a debugging strategy would be most welcome.
PS: DHCP is provided not by the router, but by a server attached to fa1.
I'll see what difference it makes; I occasionally forget to switch off the wireless on a pc when I plug it into the net.
That helps :) And since you won't use trunking on any of those ports, it also prevents configuration errors.
I note that switchport mode access does not show up in the config, which presumably means that it is the default.
There are, however, potential elephant traps, especially for someone like me who is hazy on this stuff. For example:
i) if I access my router via both ethernet and wireless, what should happen if I use only access mode?
ii) if I use different VLANs to distingish different SSIDs / classes of user, do i need to use trunking, or not?