Question

Network blocking UDP?

  • 13 July 2021
  • 6 replies
  • 518 views

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I use mosh (https://mosh.org/) to connect to some servers and have for years, which has normally worked fine, but for the last couple of weeks it has not worked over the tmobile network at all, the UDP packets never reach their destination.

I can SSH into the servers fine and run commands over SSH, but when trying to switch to mosh, which uses UDP, all UDP packets to the host are dropped and never received, while if I switch to a wireless network then they are received at the destination fine, and have tested over multiple different ISPs to different destination servers.

Support are useless, as expected when it comes to asking indepth questions about networking protocols.


6 replies

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They are indeed blocking UPD connections on 5G networks

For the unaware; UPD is a network protocol that allows you to send packets of data without waiting on a reply from the host server. It is commonly used in Live or real-time services such as voice communication on discord or online gaming, or other low-latency applications.

Customer service appears to have no knowledge of this which means it is software engineers and higher up management.

It may be to clear up the network for their home internet service which also uses 5G service.

Apparently my last comment got hit by moderation and I do not remember using vulgar language in that one so I dont know.

For me, they blamed inseego for the issue. In any case, the only current fix to using UPD is to lower your network to 4G LTE which sucks, I know. In my case, 5G is 35ms, 4G LTE is 70ms, so it really hurts.

Hopefully they revert the changes to the backend.
Your only other choice is to move to a different company.

I have the same problem. I'm a ham radio operator and some of my equipment needs to connect to servers using UDP but looks like t-mobile is blocking UDP access to internet.

Trying to talk to customer service about UDP, servers, etc, is like talking to a cow. 

Userlevel 1
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They are indeed blocking UPD on 5G connections and lying about it.

For me they tried to blame Inseego.

To fix it, I had to drop down to 4G LTE.

I use discord and play video games over 5G; Voice in discord uses UPD, chat\text uses TCP. Everything that runs through TCP works fine, while everything that uses UPD does not work on 5G.

Anti-consumer basically. Got too big for their own good.

Please note that customer service is only there to follow a script; even they are unaware of what is going on with higher ups. The fact that you even know what UPD is means that you know more than 99% of their customer service.

 

For those of you that do not know; UPD is a network protocol that typically is used for low-latency applications that do not wait for a reply from the connected server. It is most commonly used for voice communications, online gaming in Real-time, pinging, or in Mosh’s case; allows you to send packets without waiting on a packet to return; allowing it to appear latency-free. Compared to traditional where it seems really laggy because it is waiting on a reply from the remote service.

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Bump

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Still blocked for me, support still useless.

For me, it’s blocked on LTE too.

Does anyone have a way to bypass the script-readers and get to someone on their network team?

Userlevel 1
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Still blocked for me, support still useless.

For me, it’s blocked on LTE too.

Does anyone have a way to bypass the script-readers and get to someone on their network team?



Nope; I was supposed to have someone call me back a week ago after talking to the software team. Never called back then I kind of said screw it after that, started to feel like I was working a full-time job just dealing with this; Granted I am about to move soon so I dont really care right now. 

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