PBF and failover

[ClintL]

Hello all,

I had a question regarding PBF and how the failover works.

I have Internet circuit A and Internet circuit B, each through a different ISP.  All traffic and VPN tunnels go through circuit A.  I create a PBF rule to route web-browsing and ssl traffic only (using application-default) through circuit B.  It is my understanding that failover occurs when it cannot ping the gateway or whatever IP address you specify.  My question is, with my current scenario, which circuit is it using to initiate the ping?  Say it uses circuit A to initiate the ping and that circuit fails.  Wouldn't it try and failover the circuit even though circuit B is still up?  Keep in mind that you cannot create a PBF rule for the ping application as far as I know.

[HULK]

Hello ClintL ,

Could you please go through this DOC, it might give you the detail working flow for PBF with failover: How to Configure ISP Redundancy and Load Balancing

Thanks

[ssharma]

Hi Clint,

It will use Circuit B to ping the address you specify. Once the address is not reachable it will fail back to Circuit A and your web-browsing and ssl traffic will also route through Circuit A.

Also when you define PBF, I would suggest configuring it using just the destination port 80 and 443 and not web-browsing and ssl, as application recognization will take few packets back and forth. Hope this helps. Thank you.

[hshah · Accepted solution]

Hi ClintL,

It takes egress interface of PBF rule. In this case its Circuit Bs Egress interface. Kindly refer following diagram.

Where is Policy Based Forwarding (PBF) Monitoring Traffic Sourced From?

Regards,

Hardik Shah