Troubleshoot your device issues
dhilipvenkatesh's profile

Tutor

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7 Messages

Friday, March 22nd, 2019 9:07 PM

ATT LTE hotspot periodically keeps disconnection laptop VPN

ATT LTE hotspot periodically keeps disconnection laptop VPN

 

I use ATT hotspot on my mobile and use that wifi to connect my business laptop and enable VPN. Lately I am seeing that every 30 seconds or so VPN keeps reconnecting. I am having tough time finding out how to find the issue on ATT network as other hotspots like T-Mobile, Verizon, Sprint works without any issues. When I look into VPN logs I am seeing errors like "Incorrect MTU setting" and I do not see this error with other hotspots. Can someone please help finding out the MTU setting for ATT network and how to get this right for cisco VPN

Contributor

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3 Messages

5 years ago

I just found this thread and have been having the same issue. I work 100% remote with dedicated cellular hotspots, usually with AT&T or Verizon hotspots. I use AnyConnect VPN to connect to my work network. I have 3 different AT&T hotspots (Mobley, Nighthawk, & Unite Explore) and they all do the exact same thing where it connects for about 10 secs, then disconnects and repeats over and over sometimes throwing the above MTU error that was mentioned. The current location I'm in, AT&T speeds are way better than Verizon, but my Verizon hotspot works fine while AT&T constantly disconnects and reconnects. I have way more bandwidth with AT&T so I rely on them a lot more and this is becoming an issue. I'd certainly like to figure out a resolution for this. 

Contributor

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3 Messages

5 years ago

Same issue here. I upgraded my unlimited plan just for this purpose, guess I may be downgrading again if I cannot use my VPN.

Tutor

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7 Messages

5 years ago

Lot of employees in my company seem to be having same.problem with AT&T connecting to any connect VPN. In this forum as well I see so many customers having problems. I don't know how AT&T can ignore all customer complaints and say their Network is working fine. I wonder how we can bubble up this issue and get this fixed for all. Can the moderators take a note of this issue and bubble this up to the tech team who can solve this problem? @ATTHelp can you help please.

Contributor

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3 Messages

5 years ago

I have an update. My company tech sent me these instructions to run on my laptop and it worked.

 

1. Run cmd as an administrator

2. Run the command netsh interface ipv4 show subinterface

3. Type netsh interface ipv4 set subinterface "Wireless Network Connection" mtu=1320 store = persistent

 

My wireless connection was just called "wi-fi". You'll see what it was called in step 2 and use that name in the step 3. Prior to me changing my mtu to 1320, it was set at 1500. As soon as I ran this command, my ATT & VPN started playing nice again. 

 

This was just a change to my laptop and it worked. Might be worth a try if you are having the same issue. 

Contributor

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1 Message

5 years ago

Tried lowering the MTU to 1320 and rebooting - no change.

Tried lowering the MTU even further (1200) and rebooting - no change.

Verified the MTU did indeed stay persistent.

Still drops any VPN connection every 5-10 secs whereas throughput to other sites seems fine (20-50 Mbps typically).

 

Contributor

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1 Message

5 years ago

I have the issue too. I talked to one of my buddies and he told me that it seems to hav something to do with IP V4 to V6 conversion. Supposedly it should be fixed if you transition ASA to IP V6 IP address. We have not done that yet since there are a lot of dependencies. Does anybody outr there already have IP V6 and does not have the issue?

Tutor

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8 Messages

4 years ago

I'm using IPV6 and have the same issue.

One note/clue, it's fine on windows 7 today, but is an issue only on new windows 10 laptop

Contributor

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2 Messages

4 years ago

AT&T ever find a solution to this problem with hotspots/anyconnect? Add another large org that has decided to provide verizon hotspots/phones to new users because of this issue.

Contributor

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1 Message

4 years ago

I'm still looking for a resolution to this as well. 

I also tried changing MTU sizes on my VPN Concentrator (Cisco ASA) and also on my local workstation.  This did not work.  I did find in the VPN logs some errors that point to DTLS negotiation failing.  I disabled DTLS on one of my profiles and boom things worked fine.  So this is telling me that something on the AT&T side is doing something with DTLS which on my box uses UDP 443.  Is AT&T doing anything with this.

 

This use to work fine, but it appears in the August time frame, this started having issues only with users using AT&T hots pots.

Tutor

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4 Messages

4 years ago

Has anyone found a solution for this? I'm having a similar issue where my VPN stops working, but my client still shows connected (AnyConnect). My intranet and internet while on VPN do not respond. 

 

 

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