🛠️ EoIP not connecting: Tunnel troubleshooting checklist (MikroTik)

2025-10-16

The EoIP (Ethernet over IP) protocol from MikroTik is used to create an L2 tunnel over an IP network, allowing you to combine two remote local networks into a single broadcast domain.
If your EoIP tunnel does not establish (no “R” — Running flag), follow this step-by-step checklist.

1. Check IP connectivity (L3)

Before starting, make sure the routers see each other at the IP level.

Ping the remote side:

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.

Network Troubleshooting for Beginners: Listening to the Wires

2025-09-17

Introduction

Imagine: ping works, DNS responds, ports are open, mtr shows no loss, but curl returns errors like connection reset by peer or SSL handshake failed. There’s clearly a problem, but standard tools are powerless.

At such moments, the only option is to look at the actual traffic — in other words, “listen to the wires.” This process is called packet sniffing or packet analysis. In this article, we’ll go through how to use three key tools: tcpdump, sngrep, and Wireshark.