Sonicwall VPN not Working Only for AT&T Customers

VPN
1

I am scratching my head on this one and hoping y’all could provide some advice. At some point in the past few days my org started having VPN issues. We use Sonicwall. Over the course of half the day I confirmed that affected computers do have the May Windows patch, I’ve rebooted the firewall, made sure the client software is up to date, and done a ton of troubleshooting.

As weird as it sounds everything is pointing towards this issue being on AT&Ts side somewhere. I finally sent out an all org email yesterday to ask employees if the VPN was working and who their ISP was. Out of the responses every ATT customer is down and every non ATT customer is up. I went to a few places with my laptop yesterday and every ATT internet connection the VPN didn’t work, and every non ATT connection it did.

NetExtender is giving an error “Initializing Connection Parameters… Failed!” This error pops up after the client validates the user’s credentials and I am able to resolve our IP for the VPN.

So does anyone have any ideas on where to go on this or if it seems possible that it could be on ATTs end how I even go about getting it resolved? Our org is not an ATT customer.

Edit: The VPN is SSL. I forgot to include that. Also, it seems to have mysteriously fixed itself overnight.

2

Is this VPN IPSec or SSL based?

3

I just posted a similar thread.

Our subdomain used for VPN services is not working. This has been an on/off issue for a week or so it seems. AT&T does not resolve our vpn.domain.com

We had AT&T users (including myself at home) switch to a straight IP address and it works.

I’m being told to open a ticket with AT&T, but I’m not sure where/how to do so

4

Is this an SSL or IPSEC VPN?

5

Double / triple NAT ?

Do other VPN clients operate ?

6

By chance is where your VPN appliance located with TierPoint? I just had nearly this exact issue yesterday (but with IPSec) to one of our locations with AT&T. TierPoint found a bad route very early morning and after changing it the issue was immediately resolved.

7

In my experience, different ISP’s block certain VPN encryption methods for some reason. Test using different cyphers.

8

Well ours seems to have mysteriously started working overnight.

9

keep an eye on it. Mine has seemed to work on/off all week. I can connect every once in a while via FQDN and sometimes I have to use IP.