CARP protocol will not work on certain switch?



  • So I am testing pfSense using 2 physical computer that is hook to a AT&T dsl modem (with built in 4 Ethernet port).  Little crapy device.  I am testing VoIP call while turning off master:

    1. If I Make a phone call with both master/backup running, I get 2 way audio when call initiate from behind pfSense
    2. While the call is up, I turn off the "master" pfSense
    3. I will get audio (RTP packet) going out of pfSense without ANY interruption, BUT inbound audio is no more.
    4. So I DIDN'T hang up the call and wait UNTIL master comes backup, I get 2 way audio AGAIN!
    5. Now, with the same procedure as 1-3, While Master is still down, I make another phone call out behind pfSense, I will also get 2 way audio.

    So it seems the packet somehow was not able to get back into pfSense during a switch over.  Almost as if the AT&T crappy router does not know what to do with the packets when master goes down?

    So, I am not a network buff, but what is the "proper" term I am looking for when I am looking for a switch THAT WOULD work with CARP advertisement correctly?  Because it seems some switch/router will not recognize the "switch over" advertisement that CARP is putting out.

    thank you!



  • Do you have configured pfSense to use the CARP WAN IP for outbound NAT?
    If you haven't the router will send the response packets to the hosts physical MAC (which went offline) instead to virtual MAC, which is valid for both master and slave.



  • that did it!  Thank you very much for the help!


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