IPv6 RTNETLINK answers: Cannot allocate memory

 Linux, Network  Add comments
Jun 222015
 

If you get hit with “RTNETLINK answers: Cannot allocate memory” when trying to add IPv6 default gateway back after losing all IPv6 -connectivity, raise net.ipv6.route.max_size.

The defaults (on my machines) were quite small compared to IPv4:

CentOS 7.0:
# sysctl net.ipv4.route.max_size
net.ipv4.route.max_size = 2147483647
# sysctl net.ipv6.route.max_size
net.ipv6.route.max_size = 4096

CentOS 7.1:
# sysctl net.ipv4.route.max_size
net.ipv4.route.max_size = 2147483647
# sysctl net.ipv6.route.max_size
net.ipv6.route.max_size = 16384

Debian 7.8/8.1:
# sysctl net.ipv4.route.max_size
net.ipv4.route.max_size = 2147483647
# sysctl net.ipv6.route.max_size
net.ipv6.route.max_size = 4096

  One Response to “IPv6 RTNETLINK answers: Cannot allocate memory”

  1. dino says:
    03/06/2016 at 13:35

    Thanks a lot!

    This solved all my problems on Debian 7:
    sysctl net.ipv6.route.max_size = 16384

    I also put the line “net.ipv6.route.max_size = 16384” in /etc/sysctl.conf so that it will be reloaded on reboot.