Cisco AnyConnect VPN Issue

Hi @samwhitson, we are happy to help.

Are you loosing internet connection on any other devices?

Are you just loosing your VPN connection only?

Try restarting your gateway or modem, and reconnecting to your network after rebooting.

Check for interference between your gateway and your Cisco AnyConnect.

Hope this helps.

Lafayette, AT&T Community Specialist

Same here, AT&T is about to lose me as a customer and I just signed up. Get your stuff together AT&T. Spectrum and AT&T hotspot don't give me any issues, but when it comes to AnyConnect on AT&T Fiber, it's worthless, doesn't work whatsoever. I'm so mad right now. How many people are going to have to work from home thanks to COVID-19 and AT&T can't even make sure their service works with Cisco AnyConnect, one of the top VPNs out there. What a joke. Get it together AT&T!

I am having the same issue. My Cisco AnyConnect VPN disconnects and reconnects every 30-45 seconds. Half the time, it crashes the software program I use for work. If I'm on another network, including my phone's wifi hotspot, my VPN works normally. Once I get back on to AT&T fiber at home, the problem starts up again. I've contacted my IT department and they've run various tests that determined the problem is indeed AT&T.

This is almost as bad as the time I walked in on the AT&T tech sleeping on our bedroom floor after spending eight hours installing AT&T Fiber.

I am having the same problem. I upgraded my AT&T Internet and they brought out a new router. immediately my Cisco VPN  anyconnect started reconnecting many,  many times per day. AT&T insists the issue is my work computer. My work insists it’s AT&T. I never had this issue before the new upgraded Internet with router.  I can connect via my phone hotspot and don’t have the issue either.

Same problem here.  Anyconnect disconnects and reconnects whenever the gateway renews its IP lease...about every 3 minutes.  It doesn't matter whether I am using ethernet or WIFI, I'm having this problem with multiple computers, and I don't have this problem with any other provider's connection.  I've even replaced the gateway. 

AT&T still claims that this is my problem.   At this point, I have no other option that to use Comcast which (Edited per community guidelines) in my area, but I have no choice as I can't do my work.

Update: Problem solved.  Based on some experimentation, it appears that some Anyconnect versions/configurations do not play well with AT&T's LAN side implementation of dual-stack IP4/IP6.

Just disable IP6 on the LAN side within the residential gateway's configuration, and you should be good to go. 

This has everything to do with IPv6, but it can be fixed on the AnyConnect VPN/ASA side by the VPN administrator.  They need to add 'client-bypass-protocol enable' to the Group Policy for the users:

ASA(config)# group-policy your_vpn_policy attributes
ASA(config-group-policy)# client-bypass-protocol enable

This allows the IPv6 traffic to flow off of the VPN tunnel.  The disconnects every 10-15 minutes will stop once the user manually disconnects and logs in again after the setting is enabled.

I have the same problem with Cisco VPN anyconnect. The VPN periodically drops all packets and looses connectivity. ATT replaced my Gateway but the problem remains.

I disabled the IPV6 today and restarted the Gateway and hope to see the problem go away. 

My Internet connection periodically disconnects when I am on VPN. This problem started appearing about 2 months ago. It is a pain that I cannot hear or my Zoom will get disconnected during important meetings. Also my remote desktop that I use gets knocked off. 

My ATT Uverse Gateway/Router was replaced and I still see the problem. Sometimes it happens like in 2 min, sometimes in 15min.

I have disabled IPV6 on the router and restarted the router but the problem seems to be lingering still.

I had this issue for months. And ATT wasn't able to solve it.

I luckily came across this post and followed what jfsmith1982 suggested. Looks like it fixed my problem.

Just go to http://192.168.1.254 and then click "Home Network" and go to IPv6 tab.

You need your gateway access code to make this change.

Switch IPv6 to Off and Save it.