irule that would relay a DHCP request to a server on a different subnet?

LTM now supports DHCP relay in 11.1:

 

 

 

http://support.f5.com/kb/en-us/products/big-ip_ltm/releasenotes/product/relnote-ltm-11-1-0.htmlrn_new

 

Dynamic Host Configuration Protocol Relay

 

In this release, the BIG-IP system introduces the Dynamic Host Configuration Protocol (DHCP) Relay virtual server, providing the ability to proxy DHCP requests between VLANs.

 

 

 

Aaron