Hi everyone! I'm experiencing a puzzling issue with VPN users connected to our office network via SSLVPN (Sophos). Randomly, some users lose access to browse mapped drives in File Explorer, both through mapped paths and UNC paths. They can still ping the domain controller and file server, and access shares on other servers without a problem, but they get timeout errors when trying to load files from the file server. It's strange because other users can access the file server just fine at the same time.
Our setup is pretty basic: we have one Hyper-V 2025 host, a DC VM (2022), a FS VM (2022), and an RDS VM (2022) on a single subnet. We've got a Sophos firewall with a 200/200 fiber connection and static IP. Everything works as expected, even when the file browsing issue occurs. The only temporary fix I've found is to reboot the file server, which resolves the problem for a few days, but I'm really trying to figure out the root cause.
I've checked any open sessions through Computer Management and looked into the client Event Logs, including SMBClient Operation logs, but found nothing. Internet searches haven't been helpful either. I wondered if it might relate to expiring Kerberos tokens, but it seems odd for a situation where VPN users access simple Windows file shares. I just spent an hour troubleshooting for a specific user tonight, but after rebooting the file server, everything worked again right away. I'd appreciate any insight or suggestions you might have!
2 Answers
Have you checked for duplicate IP addresses? Small networks can sometimes have conflicts that lead to issues like this. It might be worth ruling that out.
You might want to reset the network stack on the file server. It's rare, but sometimes it can get corrupted. Also, ensure that any antivirus isn’t interfering and that you always use fully qualified domain names instead of relying on DNS suffixes or NTLM fallback. Those could cause access issues in your setup.
I appreciate the suggestions! I’ve already disabled the AV during troubleshooting and confirmed it’s not the culprit. I've also mapped everything using FS1.domain.local to ensure DNS resolution is working over the VPN. I’ll reset the network stack next since it’s not easy to reproduce the issue.
Let me know if that does the trick! It’s often a small tweak that can save a lot of headaches.
No duplicate IPs here. The network is small, and we have IP conflict monitoring on in the firewall. Plus, the file server has a static IP.