Routing traffic from a local subnet through a remote server (IPIP + Policy Routing)

2025-10-29

This guide will show how to configure two Linux servers so that all the Internet traffic from a specific local subnet (for example, 10.100.10.0/24) is routed not via its default gateway but through an IPIP tunnel to a remote server, which will then put that traffic onto the Internet.

This is useful if you need services in one subnet to go out to the world with the IP address of another server — for example, to bypass restrictions, centralize NAT, or hide the source.

MikroTik + Keenetic: FAQ and Step-by-Step Diagnostics

2025-09-21

This article is compiled as a “cheat sheet” for SOHO/SMB networks: common issues, their symptoms, causes, quick fixes, and diagnostic checklists. Suitable for both engineers and admins who maintain the MikroTik ↔ Keenetic bundle.

📑 Navigation

• EoIP “freezes” when transferring large files
• Site-to-Site VPN is up, but traffic doesn’t pass
• NAT breaks VPN/EoIP
• MTU/MSS: how to choose correctly
• Policy Routing (RouterOS 7)
• SMB from another subnet doesn’t work
• Quick diagnostics checklist
• Command cheat sheet
• Typical MTUs for tunnels
• NAT/Firewall exceptions matrix
• Common pitfalls
• Visualizations
• Resources and documentation

1) EoIP “freezes” when transferring large files

Symptoms: SMB/FTP hangs, speed fluctuates, RDP drops. Causes: incorrect MTU/MSS, fast-path with IPsec, NAT/Firewall errors.