Asymmetric routing occurs when the client initiates a TCP session to the server where the path towards the server runs through both Wanos instances, but the return traffic from the server to the client flows via another path without TCP-x. When this occurs the TCP sessions cannot be accelerated with TCP-x since only one way traffic is visible on the Wanos instance.
- Avoid asymmetric routing when TCP-x is enabled.
- If asymmetric routing is unavoidable and permanent, do not enable TCP-x or disable the TCP-x full transparency with the wanos.conf config option:
- Where asymmetric routing is unavoidable and temporary due to network outages, enable TCP-x Asymmetric Route Detection with the wanos.conf config option:
TCP-X Asymmetric Route Detection
TCP-X Asymmetric Route Detection is supported from v.4.2.6 onward. When enabled, TCP sessions will be tracked for certain error conditions that indicate that asymmetric routing may be present. When a session is flagged as asymmetric, the Client and Server IP address pair is added to a TCP-x bypass list for 4 hours. Further sessions between between the IP address pair will not be forwarded to the TCP accelerator until the 4 hour timeout expires.