11-02-2011 11:44 AM - edited 03-07-2019 03:11 AM
3945 is running c3900e-universalk9-mz.SPA.151-4.M2
3560e is running c3560e-universalk9-mz.150-1.SE
I've got brand new 3945's with onboard 16-port 3560e switches. On the first power up I see that there are several new vlans added that appear to be default vlans...
vlan 2 name fst2
vlan 3 name fst3
vlan 4 name fst4
vlan 5 name fst5
vlan 6 name fst6
vlan 20 name VLAN0020
vlan 21 name VLAN0021
vlan 22 name VLAN0022
vlan 23 name VLAN0023
vlan 99 name VLAN0099
I deleted the vlan.dat and reloaded the switch but these vlans come back. Does anyone know what these vlans are intended for and is there a better way to get rid of them? What does "fst" stand for?
I haven't spent much time researching the internet yet because I'm buried building a new Data Center so I thought I would try to get a quicker answer here.
Sam
11-02-2011 03:00 PM
Sam,
Sounds to me that the router has some test config from the factory left in it.
This is rebuilding the vlans at power on reload.
Try
router# delete vlan.dat
router# erase start
router# reload
See if this helps to remove these vlans
HTH
Alex
11-02-2011 03:39 PM
samuel.d.knox@boeing.com wrote:
3945 is running c3900e-universalk9-mz.SPA.151-4.M2
3560e is running c3560e-universalk9-mz.150-1.SE
I've got brand new 3945's with onboard 16-port 3560e switches. On the first power up I see that there are several new vlans added that appear to be default vlans...
vlan 2 name fst2
vlan 3 name fst3
vlan 4 name fst4
vlan 5 name fst5
vlan 6 name fst6
vlan 20 name VLAN0020
vlan 21 name VLAN0021
vlan 22 name VLAN0022
vlan 23 name VLAN0023
vlan 99 name VLAN0099
I deleted the vlan.dat and reloaded the switch but these vlans come back. Does anyone know what these vlans are intended for and is there a better way to get rid of them? What does "fst" stand for?
I haven't spent much time researching the internet yet because I'm buried building a new Data Center so I thought I would try to get a quicker answer here.
Sam
Is there a startup configuration?
Being a newer model switch, VLAN's are normally defined in the configuration, not the old-style "vlan database", and even if you delete vlan.dat, they will be re-created (and so will vlan.dat) if you leave the statements in the configuration.
Try the following
router# delete vlan.dat
router# erase startup-config
router# reload
and see if your mystery VLAN's still appear. Note that you will lose ALL configuration on the switch if you do, so don't do this if you have something important configured/are in service unless you have backed up the configuration first!
Cheers.
11-03-2011 08:15 AM
Thanks to you both for your responses. I'm going to chalk this one up to my inability to pay attention to detail. Yesterday I would have sworn that I deleted that vlan.dat AND that those vlans were gone. The reason I posted this issue is because they appeared to come back after I enabled IPV6 via the SDM command which requires a reboot to take effect. So this morning I went back through the switch again, saved the cfg to flash, deleted the vlan.dat and erased the startup cfg. The offensive vlans were gone after the reboot. I then enabled IPV6 again and the vlans are still gone after that reboot. I then executed this same scenario on the failover 3945 and those vlans are gone. I have to submit that I failed to verify properly the first time and made the really big assumption that these were some sort of new default configuration.
It is possible that I got myself out of whack. In building up these new devices, you have to connect the terminal server to the console port of the 3945. Then set up an IP on the internal routed port (gi2/0) in order to gain access to the internal console port of the switch (service-module gi2/0 session). Here's where it can get stupid... if you do a single ctrl-shift-6 +x, you drop all the way back to the terminal server. If you hit enter, you are immediately back to the switch. I have a tendancy to go too fast so I probably tried to delete the vlan.dat file on the router when I thought I was on the switch.
Sam
Sam
11-07-2011 09:42 AM
I just found out from my reseller that these vlans are all new default vlans that Cisco is sending out on these new switches and includes the VTP domain "Houston" configured. I would offer that it is a good idea to wipe out everything on every new device purchased as you want to start with a clean baseline before configuring.
My standard is to write erase, delete the vlan.dat and reboot before I begin anything. For the switches I also set the VTP mode to transparent.
Sam
04-19-2016 03:57 PM
Hi All
Were you able to find out how these extra VLANs originated ? I am seeing something similar on brand new switches and hence trying to understand how they showed up ?
thanks Kalyan
04-20-2016 04:28 AM
Hi Kalyan,
No one from Cisco ever answered this. The answer I received was from a reseller who I feel just made up a dumb answer. Since the issue wasn't impacting as I always erase the config and vlan.dat on anything I purchase new, I moved on and forgot about this until now.
Sam
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