What is ethtool?
ethtool is a powerful command-line utility available on Linux (and Linux-based devices) used to query and configure network interface cards (NICs).
It allows you to view and change low-level Ethernet settings such as link speed, duplex mode, MTU, driver information, SFP/transceiver details, and packet statistics — all without rebooting the system.
Why it matters in ST 2110 systems:
In high-bandwidth media networks (10G/25G/100G+), ethtool is essential for verifying that NICs are running at the correct speed, with proper MTU (jumbo frames), and no errors that could cause packet loss or unstable video/audio flows.
Most Useful ethtool Commands for 2110 Troubleshooting:
1. Basic interface status (recommended first command):
sudo ethtool eth0
(Replace eth0 with your interface name — find it with ip link)
Shows: current speed, duplex, auto-negotiation, link status, and driver details.
2. Detailed statistics (check for errors/drops):
sudo ethtool -S eth0
3. View SFP/transceiver information:
sudo ethtool -m eth0
Very useful to verify SFP type, speed compatibility, and optics health.
4. Set MTU (jumbo frames) – usually combined with ip command:
sudo ip link set dev eth0 mtu 9000
Then verify with ip link show eth0
5. Force speed/duplex (use cautiously):
sudo ethtool -s eth0 speed 10000 duplex full autoneg on
(Example for 10G)
Tip: Most changes made with ethtool are temporary. For permanent settings, configure them in your network manager (netplan, NetworkManager, /etc/network/interfaces, etc.).
