Knowledgebase: OpenVPN Errors
"Replay-window backtrack occurred"
Posted by on 04 September 2012 03:51

Replay-window backtrack occurred[]

If you are getting this error/warning anywhere in your connection log 

OpenVPN icon => View Log

and you step into any serious connectivtiy issues on UDP, then don't fret. 

There are two ways to resolve and optimise this issue.

The first option is to submit a ticket via and stating that you are having this issue while providing your connection log and we will switch you over to an optimized UDP configuration, which in 90% resolves exactly this typical UDP problem.

Important note: Understand that NOT automatically everyone who encounters this known and UDP typical warning, always has connection problems from this. It is solely and only for the user who encounters this error AND as a result of this, stumbles into slowdowns and similar connection issues (and this especially on heavy download tasks / torrent, but not on regular browsing).

The second option is this; since the problem is caused by using the UDP protocol, you can switch over to a TCP protocol (443) IP instead. To do this, go to the Client Area and tick the box labeled to the left of "I need a :443 IP", then once the box is ticked, hit the "I need a :443 IP" button. Proceed to download the new config, replace your current config with the new one. This will cause a 5-10% drop in speed and higher latency and less IPs available, so the first option is always reccommended first.

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