AT&T Router Prevents Mapped Drive

VPN
1

SOLVED

changed the home network to 192.168.3.0/24

as both home and office had the same network.

My small business office has a very simple environment setup:

1 - domain server (AD/DC/Fileshare)
10 - clients
1 - firewalla (configured as a router)
1 - Spectrum modem (bridged)

My home:
1 - AT&T router
1 - laptop

If I use the hotspot on my phone, I can VPN into my office, configure a mapped drive to the fileshare using the domain credentials.

If I use the AT&T router, I can VPN into the my office, and get prompted for credentials for the fileshare, but after selecting “OK or Connect” it errors out saying the network is unavailable.

The only change is the AT&T router and I get the same problem if I switch to a different PC, so I know the AT&T router is the culprit.

Any idea what could be the underlying issue preventing either the credentials from passing through or the mapped drive setup?

2

Do more troubleshooting first.

  1. Can you ping the IP address of the file server when the VPN says “connected?”

1.5) If not, is ping blocked by firewall rules of your server?

  1. Packet capture the connection attempt

VPN is an all encompassing word for a remote connection tunnel. What protocol VPN are you running?

This also may belong in /r/techsupport

3

Is the private IP range of the office and of your home the same range ? Both being 192.168.1.x for example ? If so you could change either, usually home is easier to change to something like 192.168.33.x, and that can fix it if this is the issue.

The AT&T router at home is likely where you would make the change. It is probably as simple as logging into the router at home and telling it the LAN IP it should be by changing the 3rd number in the address (called an octet) from 192.168.1.1 to 192.168.33.1 or whatever the AT&T LAN address is currently set to. This can often change the DHCP server range the AT&T router hands out so you would also have to restart/reboot the laptop or else run an cmd prompt on the laptop and execute these two commands:

ipconfig /release

ipconfig /renew

This is all predicated on my guess that the IP ranges are the same. If they aren’t the same my info above likely doesn’t apply and probably won’t help.

4

Sounds like a job for 172.16/12

5

What kind of VPN is it? If it is IPsec, check Firewall → Firewall Advanced on the AT&T gateway and flip the “ESP ALG” setting (turn it off if on and vice versa).

6

Old routers used to have “vpn passthrough” settings.

Could also be an ip conflict. That’s much more common. What’s the ip schema in the two locations? Change your home ip schema.

7

Are you connecting to the wifi provided by the AT&T router?

8

Using IP or hostname to connect?

9

1 It’s probably NOT your AT&T router, as you’re on a VPN so the router is not able to affect anything in that tunnel.

  1. You need to add a static route to your VPN config so windows knows what IP ranges to what when the VPN is on. We had this exact same issue 2 years ago when we moved from Sonicwall to Meraki, about a dozen people wouldn’t get to the file server without a static route.
10

Was about to say I bet there is ip overlap if they only have 1 server. Probably using 192.168.something

11

this was the issue. both sites were using 192.168.1.0 /24, i changed the home to 3.0/24 and it’s working now. thanks for the feedback

12

yep that was the culprit, both sites were running 192.168.1.0/24. I change the home network to 3.0 and it’s working now.

13

We had an employee using 10.0.0.0/8 for his home network and was complaining that some stuff doesn’t work when he’s at home

14

Excellent. Glad I could help. And thanks very much for this follow up comment confirming that was the issue, I can’t tell you how many times previous posters have left us hanging without an answer to which problem was occurring.

15

you’re welcome, it just seemed like the right thing to do. hope you have a wonderful weekend!