VLAN Troubles

Greg T. Grimes greg.grimes at msstate.edu
Tue Mar 6 11:04:51 CST 2012


On the cisco, do a 'show interface trunk'.  Be sure that it thinks it's 
supposed to pass those VLANs.  Make sure "Vlans allowed on trunk" includes 
the VLAN.  Same for "Vlans allowed and active in management domain".  Then 
the important one is "Vlans in spanning tree forwarding state and not 
pruned".  If it's not there then it's being pruned.  Also on your Dell 
uplink add the following line to the uplink port:

switchport access vlan add 12,22

See what that does for you.

On Tue, 6 Mar 2012, Alan Bryant wrote:

> I hope everyone is having a better workday so far than I am.
>
> I am trying to clean up the network for the Hospital I work for, and
> part of that is creating two VLAN's for two separate subnets on our
> network. Before, it was not separated by VLANs. We are also replacing
> our aged Juniper firewall with an ASA.
>
> I'm very new to VLAN's, so I am hoping this is something simple that
> you guys can help me out with.
>
> We have two switches that do not seem to be passing VLAN traffic. The
> two switches are a Dell Powerconnect 5324 & a Cisco 3560G. The Cisco
> switch appears to be functioning fine, but the Dell switch is only
> passing traffic to the Cisco that is on the default untagged VLAN1.
> Our second VLAN is not getting passed to the Cisco at all, I am not
> seeing any packets tagged with the particular vlan in Wireshark.
>
> I have Port 1 on the Dell switch connected to port 29 on the Cisco
> switch, and port 1 on the Cisco switch connected to the ASA.
>
> I have the following config on the relevant ports on the Cisco switch:
>
> interface GigabitEthernet0/1
> description ASA 5505
> switchport trunk encapsulation dot1q
> switchport mode trunk
>
> interface GigabitEthernet0/29
> description Radiology Switch
> switchport trunk encapsulation dot1q
> switchport mode trunk
>
> Here is the config for the Dell switch:
>
> interface ethernet g1
> speed 1000
> duplex full
> exit
> interface ethernet g2
> speed 1000
> duplex full
> exit
> interface ethernet g3
> speed 1000
> duplex full
> exit
> interface ethernet g4
> speed 1000
> duplex full
> exit
> interface ethernet g5
> speed 1000
> duplex full
> exit
> interface ethernet g7
> speed 1000
> duplex full
> exit
> interface ethernet g9
> speed 1000
> duplex full
> exit
> interface ethernet g10
> speed 1000
> duplex full
> exit
> interface ethernet g12
> speed 1000
> duplex full
> exit
> interface ethernet g14
> speed 1000
> duplex full
> exit
> interface ethernet g15
> speed 1000
> duplex full
> exit
> port jumbo-frame
> interface ethernet g1
> switchport mode trunk
> exit
> interface ethernet g24
> switchport mode trunk
> exit
> vlan database
> vlan 12,22
> exit
> interface range ethernet g(2,4,7,12,14-15)
> switchport access vlan 12
> exit
> interface vlan 12
> name Radiology
> exit
> interface vlan 22
> name Guest
> exit
> interface vlan 1
> exit
>
> Anyone have any ideas or pointers? Is there more information that I
> need to provide? Vlan1 works just fine, of course. It is Vlan 12 that
> is not working. Everything on the Dell switch is communicating with
> each other just fine on the same subnet.
>
>

-- 
Greg T. Grimes
Senior Network Analyst
Information Technology Services
Mississippi State University
greg.grimes at msstate.edu




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