F5 load balancer issues with TFS 2018. Adding port 8080 when coming from load balancer

If I correctly gather what you're describing, clients communicate with the F5 VIP on port 80, so the URL is simply http://www.site.com/tfs. But in some scenarios, the backend web server responds with URLs to itself, in document objects references in the HTML response, or as HTTP redirects, that include a port number (ex. ), which the browser tries and fails to access.

If that's correct, the simplest option would be to strip the port number from responses using a STREAM expression. Add an empty STREAM profile to the VIP and an iRule that looks something like this:

when HTTP_REQUEST {
    STREAM::disable
    HTTP::header remove "Accept-Encoding"
}
when HTTP_RESPONSE {
    if { ( [HTTP::header exists Location] ) and ( [HTTP::header Location] contains ":8080" ) } {
        HTTP::header replace Location [string map {":8080" ""} [HTTP::header Location]]
    } elseif { [HTTP::header value Content-Type] starts_with "text" } {
        STREAM::expression (@:8080@@}
        STREAM::enable
    }
}

The above will strip the :8080 value from the Location header if a redirect, or anywhere in the HTML response otherwise.