Error : openvpn[…]: write UDPv4: No buffer space available (code=55)

  • I everyone,

    I am trying to used PfSence/OpenVPN/Ospfd and always get the following errors in the openvpn logs:

    openvpn[…]: write UDPv4: No buffer space available (code=55)

    I have been playing with the sysctl variable to solve the issue in vain.

    My current settings are as follow:


    net.inet.udp.recvspace=262144  # Increase UDP "recieve" windows size to increase performance

    Any ideas on how to solve this issue?


    Jean Aumont

  • This is what happens when you setup broken routing, where your client gets a route to the server IP where it's connecting, within the VPN, and tries to access the server IP by using the tunnel. It has to be able to reach the server outside the tunnel not within it, and basically loops traffic and causes chaos. Don't push or setup routes on your client inside the tunnel for the IP it has to reach outside the tunnel.

Log in to reply