Hi
These are the possible reasons for the devices getting stucked up in Exstart state..
MTU mismatch
Unicast is broken. In the exstart state, the router sends a unicast packet to the neighbor to elect master and slave.
This is true unless you have a point-to-point link, in which case it sends a multicast packet. These are the possible causes:
Wrong virtual circuit (VC) mapping in an Asynchronous Transfer Mode (ATM) or Frame Relay environment in highly redundant network
MTU problem, meaning the routers can only ping a packet of a certain length
Access list is blocking the unicast packet
NAT is running on the router and is translating the unicast packet
Neighbor between PRI and BRI/dialer
Both routers have the same router ID (mis-configuration)
Unexpected DD Sequence number
"I" bit is set unexpectedly
Option field different from the last option field received in the DBD packet
BadLSReq
Neighbor sends unrecognized LSA during exchange process
Neighbor requested an LSA during exchange process that cannot be found
I guess to chek out the lowest ip address to pix and following ips to the routers and make them to become DR/BDR.I feel you can configure up like this and revert back.
regds
