netdata/health/guides/net/interface_outbound_errors.md

Understand the alert

This alert is triggered when there is a high number of outbound errors on a specific network interface in the last 10 minutes on a FreeBSD system. When you receive this alert, it means that the network interface is facing transmission-related issues, such as aborted, carrier, FIFO, heartbeat, or window errors.

Troubleshoot the alert

1. Identify the network interface with the problem Use ifconfig to get a list of all network interfaces and their error count:

   ifconfig -a
   

   Check the "Oerrs" (Outbound errors) field for each interface to find the one with the issue.

2. Check the interface speed and duplex settings The speed and duplex settings may mismatch between the network interface and the network equipment (like switches and routers) that it is connected to. Use ifconfig or ethtool to check these settings.

With ifconfig:

   ifconfig <interface_name>

If required, adjust the speed and duplex settings using ifconfig:

   ifconfig <interface_name> media <media_type>

<media_type> can be one of the following: 10baseT/UTP, 100baseTX, 1000baseTX, etc., and can include half-duplex or full-duplex. Example:

   ifconfig em0 media 1000baseTX mediaopt full-duplex

Ensure both the network interface and the connected device use the same settings.

1. Check network cables and devices Check the physical connections of the network cable to both the network interface and the network equipment it connects to. Replace the network cable if necessary. Additionally, verify if the issue is related to the connected network equipment (switches and routers).

2. Analyze network traffic Use tools like tcpdump or Wireshark to analyze the network traffic on the affected interface. This can give you insights into the root cause of the errors and help in troubleshooting device or network-related issues.

Useful resources

1. FreeBSD ifconfig man page
2. FreeBSD Handbook - Configuring the Network