MTU for XBOX live mutliplayer gaming on 5g home broadband

[Lexx289]

I am struggling to get my Xbox to work on Xbox live. Doing some googling it seems that the MTU is too low, it is 1360 and should be about 1385 to be able to work properly. I have rung three who seem to have no knowledge of what an MTU is and have sent me to the ombudsman. I have logged into the router (H122-373) and increased the MTU manually however it will not pull through onto my XBOX. I have put it in the DMZ, enabled UPNP and generally faffed with it as much as i can but the MTU on the XBOX does not change. I am assuming this is what is being sent from three and so it is something to be changed at three's end...

Does anyone else have any experience of this, or have any issues with XBOX live and home broadband 5g? or can they get it to work, cheers

[Hman]

Hi,

Had the exact same issue but have been able to resolve it thanks to this thread!!! 

Went and picked up the same 5G router today (MC801A) and as soon as I connected my Xbox to it, I was having MTU issues straight away, was getting beyond frustrated with it at how it simply will not work on Xbox servers and nearly threw it out the window. After hours of searching and finding this solution I went down a rabbit hole to find out why these routers don't work with Xbox

Essentially, You are finding yourself up against a limitation of 3’s (and every other mobile broadband provider) mobile network which uses Carrier Grade NAT (CGNAT) resulting in a double NAT or ‘strict NAT type’ which consoles  object to, as it forces you to share an IP address with other users, preventing direct  connections for online features that need unique IP’s like p2p gaming and voice chat, therefore your LAN cannot be addressed outside the shared IP 

What Ridzzog and Dawiiss brilliantly explain is setting up a static IP on the router and manually port forwarding your Xbox to bypass the CGNAT using IPv4 

The fact that Three have not addressed this for what seems to be years, but still continue to advertise them as perfect for gaming when they are not unless you do your own IT is borderline fraud!!! 

[Ryan92abc]

I've got the exact problem, can't play any multiplayer games, MTU is currently 1360 and I dont know how to change it on my router. It's only started happening from today which is weird because ive had the three router for about 2 months. Going to ring them in the morning but by the sounds of it they're useless. I'll keep you updated 👍

[luke_ellis]

Just to say that I've had the same issue for Xbox multiplayer. The WiFi offered was really fast and seemed great, but the MTU displayed was 1352 on my Xbox. I see from this thread that the minimum MTU for Xbox online player is 1384, and this is not something Three can resolve.

Thankfully I found this thread before in my cooling off period.

[Sharkbait]

Was this ever solved? I have just got Three 5g and having this issue. My friend has an older router, and no issues - is it the router model?

[tmwsccsh]

Well, interestingly, I have had this issue for about a year or more and it now seems to have gone away.

I did make a change on the router though - changed the APN as some people have suggested here in this thread.  Previously I was using the 3internet one, now I am using three.co.uk with PDP type of IPv4v6 and that is working.

From a command prompt on a Windows PC if I "ping 8.8.8.8 -f -l 1352' that returns fine, suggesting 1380 as the max size MTU I can send (1352 from the ping plus the 28 overhead).  Increasing it to 1353 then the "Packet needs to be fragmented but DF set" message appears.  1352 however will give a consistent and reliable response. 

Prior to changing the APN the most I could put through was 1324.

This was changed about a week ago now and all has been fine since...

I had ordered a BT line to go in next week as I am out of contract with 3 in April - now this is working, and was the only reason I was looking to change, I may cancel the BT install.  Will see how the weekend goes and then decide.

[tmwsccsh]

Sorry, should have added, Router is the ZTE MC801A, Last Update: 2023-04-05 18:33:02

[Cbak109]

Just phoned 3 to complain about this and my mtu on pc is 1342.  I've got 14 months left on my contract.  They have said they can't increase the mtu size ???

Can I cancel ??

[Jackmorris59]

When are you going to fix this you’ve miss sold to thousands!!!

[shadwuk]

I have this too and I'm now out of contract so I'm considering leaving.  Between this and the flakey random disconnect problems what would be a totally excellent service is made extremely poor.