Squid with OPT1 for backup proxy

  • Hello,

    My pfsense have one link WAN and one link OPT1. The OPT1 is a private network with dedicated SDSL. My traffic is routing well through PFSENSE (WAN goes to WAN, Intranet to OPT1).
    I want to know if it's possible to backup my WAN connection with a proxy available in OPT1. My idea is to enable a Squid in transparent mode on the PFSENSE then rules will be something like :

    • WAN is up, Squid retreive data from WAN link.
    • WAN is down, Squid retreive data from parent proxy located in OPT1 network.

    It is possible, i'm totally newbie with squid…