gistfile1.txt

table <vhost1> { 10.20.30.40 10.20.30.50 }

table <vhost2> { 10.20.30.60 10.20.30.70 }

http protocol "vhosts" {
        match request quick header "Host" value "vhost1.test.com" forward to <vhost1>
        match request quick header "Host" value "vhost2.test.com" forward to <vhost2>
}

relay "vhosts" {
        listen on 192.168.128.18 port 80
        protocol "vhosts"
        forward to <vhost1> 
        forward to <vhost2>
}