Redirect Loop

First iRule modified:

when HTTP_REQUEST {
    if { ( [HTTP::uri] equals "/default" ) and not ( [HTTP::cookie exists SITEA] ) } {
        HTTP::respond 302 Location "http://[HTTP::host]/default" "Set-Cookie" "SITEA=1;path=/"
    } elseif { not ( [HTTP::cookie exists SITEA] ) } {
        HTTP::respond 302 Location "http://www.bbb.com/communication"
    } 
}

And no, you no longer need to modify the HTML link with a query string. So the above basically says:

1. if the request to site A is for "/default" and the SITEA cookie doesn't exist, redirect to itself and set the SITEA cookie (presumably this request is coming from site B).
2. Else if the request is not for "/default" and the SITEA cookie doesn't exist, redirect to site B.
3. And by default, if the request is not for "/default" and the SITEA cookie exists, do nothing (pass the traffic through to site A).