Poor Wireguard throughput over 2degrees/Warehouse Mobile mobile network

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siyuan

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#319747 28-May-2025 17:23

I've been observing for a few weeks, but I'm now convinced something changed on 2degrees/Warehouse Mobile. It started when streaming music from my home server over Wireguard started dropping every few seconds. It was fine a couple months ago though, music would stream fine mostly, except the occasional brief drop a couple times an hour perhaps. It's has gotten so bad now that I can't even login my router's web UI over Wireguard due to connections dropping. And forget watching the IP cameras, I'd be lucky if I can even hear a sound coming through.

The problem seems to be limited to Wireguard however, other types connections seem to be fine, e.g. general web browsing and YouTube. Not saying the speed is great (Auckland, pretty much anywhere), but usable in general. I've also tried to isolate the problem, things I've tried:

Accessing my home network over Wireguard from work WiFi, it's fine and very fast. This applies to both a PC and the same mobile phone, in fact I can even saturate my gigabit fibre at home from work.
Back to mobile network, accessing home-hosted web services over HTTPS and that's also fine.
Routing all my traffic over Wireguard to my home network as my gateway and do a test in the Speedtest.net app on my phone, the speeds seem to hover around 1Mbps, but the test fails due to dropped connections I believe.

Perhaps something about handling UDP connections has changed on 2degrees/Warehouse Mobile? Has anyone experienced anything similar?

muppet

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#3377728 28-May-2025 18:10

Sounds like an MTU issue. You doing MSS clamping on your WG interface?

siyuan

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#3377730 28-May-2025 18:25

It looks like it's using the default MTU of 1420. What would be a sensible value? I assume it has to be set on all peers?

MaxineN

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#3377786 28-May-2025 20:40

Usually the defaults are sane and a MTU of 1420 is the default on WG.

There is something funky going on.

Doing a multithreaded speedtest via openspeedtest I get a pitiful sub 15mbps both ways after the initial burst when I wireguard back home (Vetta/Quic).

Testing against 2degrees Auckland I pull almost 100mbps download and 15mbps upload. I am on a cell site that during quiet hours pulls in excess of 250mbps on DL. In fact, doing a second run nets me 180mbps DL, same 15mbps up (upload is normal).

Running the same test with the openspeedtest docker exposed via NPM... 2mbps DL, less than 1mbps up.

Going to do some packet inspection.

Ramblings from a mysterious lady who's into tech. Warning I may often create zingers.

MaxineN

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#3377791 28-May-2025 21:24

@Sounddude 🙋‍♀️

I have confirmed I have the opposite issue of OP, and I have some pcaps I would love to throw at an engineer. Who's the best contact? pcaps reveal an excessive amount out of order when under WG. Don't have another ISP to validate if it's just a an issue between AS9790 and AS64073.

What I have tested:

Testing via Spark straight to the openspeedtest docker via NPM to my fibre connection breaks triple digit downloads (almost 200mbps dl).

Testing 2degrees under WG gets me sub-optimal results (15mbps both ways) vs it behind NPM and no wg (2mbps both ways).

Testing 2degrees no WG to openspeedtest via http nets me better (25mbps DL) but it's still not triple digits. Barely enough for a 4k stream ;).

Can't replicate OP's 1mbps speedtest though... I just almost hit capacity of the tower and my distance to it (so almost 200mbps on the downlink)

Not in a position to drop the MTU on the wg0 interface but I could spin up an alternative to do additional testing.

Tempted to spin up OVPN...

Edit: as of 11pm... My issue has gone away... 🤔

Ramblings from a mysterious lady who's into tech. Warning I may often create zingers.

siyuan

189 posts

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#3378197 29-May-2025 22:02

I still need more testing, but setting MTU to 1300 worked much much better. At least I can stream my music without much problem again.

siyuan

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#3381234 6-Jun-2025 13:03

By experimenting with pinging my home network, I settled with an MTU of 1280 and it's been working reliably for me now.

 
$ ping -M do -s 1300 server_ip -c 1 
PING server_ip (server_ip) 1300(1328) bytes of data. 
ping: sendmsg: Message too long 
 
$ ping -M do -s 1252 server_ip -c 1 
PING server_ip (server_ip) 1252(1280) bytes of data. 
1260 bytes from server_ip: icmp_seq=1 ttl=63 time=160 ms