When I'm connected to a certain VPN I have to use a proxy configuration file to access the internet. I think that iMessage uses a port that is blocked by the proxy (5223). Is there a way to direct iMessage around the VPN so that the port is accessible?
1Doubtful; You will have to see about getting that port unblocked.– RamhoundFeb 25, 2014 at 16:17
You're telling me there's literally no way to redirect traffic around a VPN for a specific application so that it just accesses the internet on my wifi through my router rather than through the VPN and its proxy?– JuJoDiFeb 25, 2014 at 16:35
That is not a standard service (ie. HTTP based or that supports socks proxy) that you could just redirect through a "standard" proxy. There doesn't seem to be any way to do it indeed.– fede.evolFeb 25, 2014 at 16:40
Since you have to use a proxy and thats whats blocking the port there isn't much you can do about it. Without the proxy the VPN doesn't have access to the interent only intranet.– RamhoundFeb 25, 2014 at 16:53
I believe you would want to look into making an SSH Tunnel and forwarding all your traffic through the ssh tunnel. Its not a simple thing to do however. Also you will run into issues if you are looking at UDP vs TCP traffic as you will have to wrap it up somehow.
Furthermore you are missing some ports used by iMessage (http://support.apple.com/en-us/HT202078) In addition to 5223 it also uses 80 (http) and 443 (ssl).
Your VPN could be blocking port 5223 - or perhaps they could be blocking any hosts run by apple. I believe this is what my office does.
In theory you could setup SSH port forwarding for TCP port 80,443,5223 and this "might" open up iMessage for you. Its more complex than I can explain right now as my wife is telling me to come to bed right now.