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loop on CISCO ASA 5505

Hello,

I have a problem with the configuration of my Cisco ASA 5505. I have 2 interfaces 0/2 and 0/3 which are each connected to a switch SW1 and SW2.

On these interfaces I have a trunk multiple VLANs. When I plug the interface 0/2 on the SW1 no problem. But when I add the interface 0/3 on SW2, I have a loop that is.

I made a shema to understand.

ASA-loop.PNG

the 5505 does not support the spanning tree, the spanning tree is configured on two switches.

Is there a solution to activat the interface 0/3 when 0/2 is down ?

Config of  ASA (0/3 is shutdown to avoid the loop) :

interface Ethernet0 / 2

  switchport trunk allowed vlan 2-4

  switchport mode trunk

!

interface Ethernet0 / 3

  switchport trunk allowed vlan 2-4

  switchport mode trunk

  shutdown

!

6 Replies 6

cadet alain
VIP Alumni
VIP Alumni

Hi,

you can use the redundant interface feature:

http://www.cisco.com/en/US/docs/security/asa/asa80/configuration/guide/intrface.html#wp1045838

Regards

Alain

Don't forget to rate helpful posts.

Don't forget to rate helpful posts.

thank you, I'll watch.

I found this command that also seems to solve my problem:

switchport protected (on both interfaces)

Not familiar with the operation of this command. I'll try your method which is more understandable.

Hi,

switchport protected will prevent interfaces with this feature to communicate, this is also called pvlan edge feature but it will not prevent STP loops to my best knowledge.

Regards

Alain

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Don't forget to rate helpful posts.

unfortunately I do not have controls available ...

FW-B1#

FW-B1# conf t

FW-B1(config)# int ?

configure mode commands/options:

  Ethernet  IEEE 802.3

  Vlan      Catalyst Vlans

 

FW-B1(config)# int

Hi,

you can also try this on the switch side:

http://www.the-lan-man.net/wordpress/2010/asa-5505-switch-redundancy/

Regards

Alain

Don't forget to rate helpful posts.

Don't forget to rate helpful posts.

thank you for your help Alain,

unfortunately i don't have a 3750 stack behind but I have only 2 DELL 3524 without stack.

there is just a port-channel between swtichs.

I'll keep looking, but my case seems to have no solution

thank you again


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