ASA - Transparent failover pair without STP possible?

[pictuscat]

Hello,

I’m trying to see if it is possible to introduce two transparent ASA 5520s in an Active/Standby pair between 2 switches that don't currently run any form of STP.

Does anyone know if this is a supported configuration? I’m aware that if both ASA units thought that they were the master this could introduce a L2 loop but under normal operation would a failover succeed without creating a loop or is STP definitely required to achieve this set-up?

I'm trying to avoid having to use routed mode in this instance as re-numbering the address spaces would be quite difficult for this particular scenario.

Many thanks,

Andy

[Julio Carvajal · Accepted solution]

Hello Andy,

Exactly, while one unit is on standby mode it will not introduce any loop as it will not be forwarding any data.

That being said it's a supported scenario

For more information about Core and Security Networking follow my website at http://laguiadelnetworking.com

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Cheers,

Julio Carvajal Segura

[pictuscat]

Thanks Julio. I'm going to recommend the routed mode even though it's likely to cause some short-term pain. But it's good to know that transparent mode should be possible if that's not an option.