Linux: Neighbour Table Overflow Error and Solution

by

The “Neighbour Table Overflow” error in Linux can occur when the system’s neighbor cache table, which is used to store information about network neighbors such as ARP cache entries, has become full. This can result in network connectivity issues and may cause other problems, such as high network latency or dropped packets.

Here are a few possible solutions to this issue:

  1. Increase the size of the neighbor cache table: You can increase the size of the neighbor cache table by modifying the net.ipv4.neigh.default.gc_thresh1 and net.ipv4.neigh.default.gc_thresh2 values in the /etc/sysctl.conf file and then restarting the network service.
  2. Decrease ARP cache timeout: Decreasing the ARP cache timeout value can help prevent the neighbor cache table from becoming full. You can decrease the ARP cache timeout value by modifying the net.ipv4.neigh.default.gc_stale_time value in the /etc/sysctl.conf file and then restarting the network service.
  3. Enable gratuitous ARP: Gratuitous ARP is a type of ARP broadcast that is used to update other devices on the network with the mapping between an IP address and a MAC address. Enabling gratuitous ARP can help reduce the number of ARP cache entries in the neighbor cache table and prevent the “Neighbour Table Overflow” error.
  4. Upgrade the network hardware: If the neighbor cache table is frequently becoming full, upgrading the network hardware, such as the network interface card or switch, may help resolve the issue.

If you are still encountering the “Neighbour Table Overflow” error after trying these solutions, you may need to consult the documentation or seek help from the Linux community for further assistance.

Leave a Comment