HSRP
From Cisco Clue
Overview
HSRP (Hot Standby Router Protocol) is Cisco's protocol for providing redundant gateways to host computers that don't support routing protocols. The IETF standard protocol is VRRP.
Tips
HSRP and dhcp-relay
Because of the two IP helper-address statements on the routers running HSRP I get 2 DHCP requests that are identical. The problem is unavoidable (insert plea for 'make HSRP standby interface inactive regarding all other IP functions'). There is no way at this time to make a single restaurant supply request happen and to have it forwarded with SRC IP == standby IP.
OTOH, comments on cisco-nsp indicate that this doesn't seem to cause harm - we've run HSRP with ISC DHCPD and with MacOS X Server DHCPD, and in both cases, both replies are identical, and the clients don't seem to mind.
