Squid load balancing with proxy.pac

function FindProxyForURL(url, host) {

 

// If the hostname matches, send direct.

    if (dnsDomainIs(host, "intranet.domain.com") ||

        shExpMatch(host, "(*.abcdomain.com|abcdomain.com)"))

        return "DIRECT";

 

// If the protocol or URL matches, send direct.

    if (url.substring(0, 4)=="ftp:" ||

        shExpMatch(url, "http://abcdomain.com/folder/*"))

        return "DIRECT";

 

// If the requested website is hosted within the internal network, send direct.

    if (isPlainHostName(host) ||

        shExpMatch(host, "*.local") ||

        isInNet(dnsResolve(host), "10.0.0.0", "255.0.0.0") ||

        isInNet(dnsResolve(host), "172.16.0.0",  "255.240.0.0") ||

        isInNet(dnsResolve(host), "192.168.0.0",  "255.255.0.0") ||

        isInNet(dnsResolve(host), "127.0.0.0", "255.255.255.0"))

        return "DIRECT";

 

// Round robin based on source ip address, with failover

// Find the 4th octet

var myip=myIpAddress()

var ipbits=myip.split(".")

var myseg=parseInt(ipbits[3])

// Check to see if the 4th octect is even or odd

if (myseg & 1) {

     // Odd

     return "PROXY 172.18.0.160:9090; PROXY 172.18.0.159:9090; DIRECT";

}

else {

     // Even

     return  "PROXY 172.18.0.159:9090; PROXY 172.18.0.160:9090; DIRECT";

}

}

Configure squid for multiple outgoing addresses

https://www.tastyplacement.com/squid-proxy-multiple-outgoing-ip-addresses

Then configure the client to round robin with proxy.pac on the different ports