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Use cases for Layer 2 forwarding Virtual servers?

Hello Everyone !

I understood what is Layer2 forwarding VS & how it works but could someone explain what are the use case scenarios for Layer2 Forwarding VS ? Has anyone deployed this ?

Thank You


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Comment made 19-Apr-2018 by crodriguez

Have you looked at Lori MacVittie's (F5) article, Back to Basics: The Many Modes of Proxies? It provides some information on L2 Forwarding Virtual Servers. Basically, it is not uncommon for a BIG-IP system to be placed in a network location where it sits in the path between two existing networks. As a default-deny system, any traffic that is not explicitly allowed by the BIG-IP system's configuration is denied. Therefore, if access is needed between networks where the BIG-IP system is in the path, a forwarding virtual server provides an ideal solution. A forwarding virtual server essentially changes your BIG-IP system from full-proxy mode to packet-by-packet proxy mode, at least for the traffic the forwarding virtual server processes:

The BIG-IP system provides forwarding services in two ways:

  • For simple packet forwarding, where the destination is not based on a pooled resource but simply on a routing table, a forwarding IP virtual server turns the BIG-IP full proxy into a packet layer forwarder.
  • For situations where a proxy should be used to bridge two different collision domains, a layer 2 forwarding virtual server can be used, and configured to be an opaque, semi-opaque, or transparent bridge. (From Lori's article.) A forwarding layer 2 virtual server shares the same IP address as a node in an associate VLAN, and is used in conjunction with a VLAN group.

Does this help?

Comment made 24-Apr-2018 by murali 255

Thank you crodriguez ! i will check that article.

Comment made 27-Jun-2018 by murali 255

i have gone through the article but i didn't get the where this can be used ? if it's like a network bridge will the L2 VS forwards the packet based on destination MAC ? i'm not sure how this works.

Thank You

Comment made 27-Jun-2018 by crodriguez

Try this article for some additional detail on VLAN groups and how a Forwarding L2 can work under the covers to bridge clients and servers in the same address space but different VLANs: https://devcentral.f5.com/questions/vlan-group-23088

Comment made 27-Jun-2018 by swjo 311


Can I ask better way?

using L2 forwarding.

using L3 forwarding & change db vlangroup.forwarding.override value false?

with regards,


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