in one of my customer place we are facing some ISP failover issue.below is the Network Setup details
1) we have airtel internet lease line with static public IP with /30
2) this airtel links connect to Cisco router 2801 with
3) the router 2801 interface f0/1 connected to sonicwall firewall on X1 interface.
4) this Sonicwall operates in transparent mode connected to LAN swicthes
5) The MTNL DSL internet MOdem (256kbps) is connected to SOnicwall x2 interface & connects the users to the internet when ever primary airtel links goes down.
"now the problem is here , once the main airtel links goes down the sonicwall firewall automatically swicth over to MTNL DSL Internet link.& failover works fine . but once the Airtel links comes back. the sonicwall doesnot swicth over the to primary airtel links. if we want traffic shuold go to airtel link , we need to manually clear the arp entries in the sonicwall firewall after then it switch to airtel links.we checked with sonicewall technical support team they say that may be some issue with cisco router. any idea what could be the problem."
Note : Static ARP entries has done in the Router for the connected interface of the firewall.
attached the running config of the router & Network Diagram