Apple reviewer can't connect

I recently published a game on the appstore. Unfortunately, the during the App Review they can't connect to my server. And I fail to understand why. The game supports both ipv4 and ipv6 and is running live since 8 months on Android/Windows with an average of 200~ concurrent players without any issue. I ported it on iOS (it's written in C++ and use raknet for the socket) and It's working well on my Apple devices : Ipad, iphone 5C, iphone SE 2020, and I even tested the game with 13 different Iphone devices on Amazon Device Farm and the multiplayer worked.


The game uses only UDP sockets to connect to a server on port 53487(ipv4) and 53488(ipv6). I didn't setup DNS64/NAT64 because it works without it on other platforms.


They is no way to fix this issue, because I just can't reproduce the issue the App Reviewers are facing and after one week of testing every situation possible to find why they can't connect, I'm out of ideas and I'm starting to think that maybe the issue doesn't come from me but from Apple's firewall or something specific to App Reviewers ? (such as blocked port, permissions...?)

I would really appreciate some help.


Thanks

Accepted Reply

Hello @Jteam ,
Unfortunately we didn't find a solution. But we noticed in the past months that many developers are facing the same issue (UDP socket don't go through their VPN, while TCP does)
So there is definitely something wrong on Apple reviewer's side.

source :
https://developer.apple.com/forums/thread/650612
https://developer.apple.com/forums/thread/133980
https://developer.apple.com/forums/thread/132096
https://developer.apple.com/forums/thread/131961
https://developer.apple.com/forums/thread/131152
https://developer.apple.com/forums/thread/130624
https://developer.apple.com/forums/thread/651264

Replies

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Perhaps TN2431 can help. Such as the info at Network conditions

Post not yet marked as solved Up vote reply of KMT Down vote reply of KMT

The game uses only UDP sockets to connect to a server on port 53487(ipv4) and 53488(ipv6). I didn't setup DNS64/NAT64 because it works without it on other platforms.


Well now you're on a new platform. I'm sure Apple is inside a corporate network with all kinds of firewalls and deep packet inspection. Some of my customers on corporate networks sometimes can't connect to my server using TCP on port 80/443.


The easiest solution is to have your server accept TCP over port 80 as a fallback. You don't need to have great response or low latency or anything. You just need to pass app review.

For us it is the exact same problem. If somebody found a solution, it would be nice if he/she could share it. The only explaination I have left is a Firewall that blocks all inbound UDP traffic on apples side.
Hello @Jteam ,
Unfortunately we didn't find a solution. But we noticed in the past months that many developers are facing the same issue (UDP socket don't go through their VPN, while TCP does)
So there is definitely something wrong on Apple reviewer's side.

source :
https://developer.apple.com/forums/thread/650612
https://developer.apple.com/forums/thread/133980
https://developer.apple.com/forums/thread/132096
https://developer.apple.com/forums/thread/131961
https://developer.apple.com/forums/thread/131152
https://developer.apple.com/forums/thread/130624
https://developer.apple.com/forums/thread/651264
I couldn't edit my main post, so here is my last update on the subject.

I fixed the issue I was facing by offering a TCP alternative to connect to my game servers. So the game will first try to connect in UDP and if it doesn't work, it will try to connect with TCP.

The game has now been accepted by Apple reviewers, they can connect only with TCP for some reasons through their VPN. And since then thousand of users are successfully playing online (100% of them in UDP, no one connected on the TCP servers yet).