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How to Handle VPN Conflicts with Identical Subnets?

December 6, 2025 5 answers
Asked by TechGuru99
Hey all! I've got a new client with many remote users connecting to their main office via a Sophos Remote Access IPSec VPN. The catch? Their office LAN is set up on the 192.168.1.x /24 VLAN, and many remote users have home networks on the same VLAN, which leads to some conflicts. Ideally, we'd change the office LAN to a different IP range to avoid these issues, which is the long-term plan, but we're not ready to make that switch just yet. We have adjusted the gateway from .1 to .250 to solve some problems, but there are still users facing conflicts. I'm exploring ways to work around this without causing any downtime or disruptions since the client is sensitive about interruptions. One idea I have is to change the office LAN to a /16 subnet. This would maintain the current network addresses but create a different Net ID than the users' networks. However, I worry about forgotten devices on the network—if some devices are still on the /24 range and share IPs, will they continue to function properly? Any suggestions?
network solutions remote access Sophos subnet conflict sysadmin System Operations vpn

Answers

HomeRouterHero
One option is asking your remote users to adjust their home network ranges. It's not the best solution, but it could help in the interim while you plan a more permanent fix with the Sophos configuration.
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IPConfusionFixer
You might want to try connecting by hostname instead of IP. It might help bypass some of those pesky conflicts, as long as the DNS resolution is working well.
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SecureConnection88
Consider setting up SNAT and DNAT on both sides of your VPN. This can help reroute traffic appropriately and reduce the chances of conflict.
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VLANMaster3000
Why not create a separate VLAN/subnet specifically for VPN traffic? Something like a 10.0.x.x range could work well to isolate the VPN connections and avoid the confusions all together.
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NetworkNinja77
For situations like this, I've found that adding specific routes to your routing table can help direct traffic effectively, even if there are subnet overlaps. It's a bit manual but definitely quick and effective. Just point the individual IPs to the VPN gateway, and you're good to go!
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