Solved

gns3 - switchport trunk allow vlan error

Posted on 2016-11-04
4
103 Views
Last Modified: 2016-11-05
I am using GNS3 and am trying to have only one vlan on the trunk. I did the command below and I got an error. Then I tried to remove the existing VLANs but it did not remove them from the vlan db. Any thoughts? Thx

sw2(config-if)#switchport trunk allowed vlan 255
Command rejected: Bad VLAN allowed list. You have to include all default vlans, e.g. 1-2,1002-1005.
0
Comment
Question by:leblanc
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
4 Comments
 
LVL 29

Accepted Solution

by:
Predrag Jovic earned 400 total points
ID: 41875163
In some old Cisco IOS versions you had to include VLANs 1002-1005 on trunks (and also VLAN 1 - if I remember correctly), but typically that's not the case anymore. Most likely problem is with Ethernet card inserted in router that you are using to emulate switch since GNS3 does not emulate switches (at least not when I checked it last time).

VLANs 1002 - 1005 are by default present for historical purpose (FDDI and token ring) on switches and can't be deleted. Don't worry about it, you can safely ignore that message for production. For testing purpose use:

sw2(config-if)# switchport trunk native vlan 255
sw2(config-if)# switchport trunk allowed vlan 1,255,1002-1005
0
 
LVL 6

Assisted Solution

by:Niten Kumar
Niten Kumar earned 100 total points
ID: 41875166
Note: VLANs 1 and 1002 through 1005 are reserved VLANs and cannot be removed from any trunk link.

To add a VLAN to the trunk, issue the
switchport trunk allowed vlan add vlan-list

Open in new window

command.

sw2(config-if)#switchport trunk allowed vlan add 255

Open in new window


You can simulate switches really nicely with IOU.  Refer to the following link.

http://letusexplain.blogspot.com/2015/07/cisco-iou-l2-l3-lab-with-gns3-switching.html
0
 
LVL 29

Expert Comment

by:Predrag Jovic
ID: 41875167
Niten Kumar, those VLANs can be removed from trunks, no problems with that.
Even Packet tracer will not argue about that (at least with 3560):

Switch(config-if)#switchport trunk allowed vlan 10
Switch(config-if)#do sh int trunk
Port        Mode         Encapsulation  Status        Native vlan
Gig0/1      on           802.1q         trunking      1

Port        Vlans allowed on trunk
Gig0/1      10

Switches can be emulated in UNL also (not sure about etherchannel, but I did not watch any videos so far). But, as a first impression, I like the tool (although did not waste too much time with it and just tested simple things, I am still getting familiar with it).
0
 
LVL 1

Author Comment

by:leblanc
ID: 41875636
When you configure the VLAN, it is added automatically to the trunk.
The command sw2(config-if)# switchport trunk allowed vlan 1,255,1002-1005 worked. It looks like with the swithcing module I use for the router, you have to manually allow those default VLANs. Thx
0

Featured Post

NFR key for Veeam Backup for Microsoft Office 365

Veeam is happy to provide a free NFR license (for 1 year, up to 10 users). This license allows for the non‑production use of Veeam Backup for Microsoft Office 365 in your home lab without any feature limitations.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Switched virtual interface on layer 2 switch 2 50
adjusting startup config 6 76
(Same as parent Folder) Host (A) IP: x.x.x.x 7 61
Rogue RDP Connections 5 108
Please see preceding article here: http://www.experts-exchange.com/Networking/Operating_Systems/A_11209-Root-Bridge-Election.html Figure 1 After Root Bridge has been elected, then what?..... Let's start by defining a Root Port in la…
There are times where you would like to have access to information that is only available from a different network. This network could be down the hall, or across country. If each of the network sites have access to the internet, you can create a ne…
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…

734 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question