This post is was written for users from Luxembourg with Post (post.lu) as their internet provider. The router used is Fritzbox.
Lately I wanted to play Diablo on my PlayStation4 with my friend via PlayStation Network. After buying a “PlayStation Plus” membership, I thought that I was ready to go. Well, far from that. My friend and I were not able to join each other game. We spend quite some time configuring our PlayStation settings and modifying the router settings (I thought it was a firewall issue so I removed all firewall rules for the PlayStation).
On the internet there are a lot of posts describing this issue with different approaches to solve it. The first good hint was a guy how asked if the voice chat on PlayStation party works.
Quick Hint
Create a PlayStation party with voice chat. If you cannot hear your friend, the problem is network related. PlayStation System should give you a hint on how to solve the issue.
So we created a party and tried to voice chat with each other. Very soon after the creation of the party the PlayStation popped a notification citing that the communication cannot be established due to a NAT issue.
Now we had a track. I went to the PlayStation Settings, Network and executed a “Test Internet Connection”. After the test execution succeeded I had a screen similar to this one:
There it is. NAT type 3. Here PlayStation Statement on NAT 3 connection:
“With Type 3, communication with other PS4™ systems might be impossible, or the PS4™ system's network features might be limited.”
Quick Hint
By testing your internet connection via PlayStation 4 you will get the NAT type. If the NAT type is 3, a connection with PlayStation Network is not possible. Thus, you cannot join your friend’s party.
Now I knew what I have to search for. Very quickly I found a post in the PlayStation forum where a user has the exact same issue as my friend and I do.
The user Obiwan_Kenoby explained that the issue is network related. In fact, the Luxembourgish Post network is IPv6 while the connection to the PlayStation servers is still IPv4. The additional translation from IPv6 to IPv4 takes some time which leads to a NAT of type 3.
The user in the forum (ESCORT-RS2000) said that there is an additional modification which needs to be done on the Post.lu site. So I contacted a friend of mine asking if the “IPv6 to IPv4” translation really needs to be done.
He confirmed and told me that for changing the NAT Type from 3 to 2 a setting on the post network has to be changed. I should go to https://www.luxfibre.lu/portal and from where I can change the setting. ATTENTION: This options costs 1.99€/month.
The setting is active within 10 minutes. The NAT Type should now by NAT 2 and you should be able play over the PlayStation network with your friend.
At A glance
Check your NAT Type (Nat type 2 is needed)
Activate the IPv4 setting (ATTENTION: 1.99 €/month)
If you have any questions, just leave a comment.
This kept me busy: 150 minutes
References
Nat3 image from: http://www.ps3hax.net/tag/skfu/
PlayStation Statement: http://manuals.playstation.net/document/en/ps4/settings/nw_test.html
PlayStation forum: http://community.eu.playstation.com/t5/PS4-Support/Ps4-nat-typ-fritzbox-7390/td-p/22151521