Duplicate packet drop error - OpenVPN

RouterOS General
1

Hello guys,

Long story short, I’ve used OpenVPN on a server behind the mikrotik but I had few problems so I’ve decided to setup OVPN server on the mikrotik (Hex). I’ve made the settings and everything seemed to be ok but when the client is connected to the server the mikrotik logs the following error:

duplicate packet, dropping

Also in the terminal pops up the following echo

17:22:38 echo: ovpn,debug,error,,,,,,,,,l2tp,info,,debug,,,critical,,,,,,,,,,,,,warning duplicate packet, dropp
ing

I’ve tried to reconfigure the server but the error keeps coming on every connection. However I’m able to connect to the server and everything seems to work. Do you have any idea where this error may come from?

2

No one has any idea how to deal with this problem? I’m seriously stuck at this and the only thread I found with the same problem doesn’t seems to deal with it.

3

Hi

Do you see it often? If not just ignore, it’s informative, and Tik did the right thing already: dropped the duplicate.

It might be the consequence of tcp over tcp: opvn tunnel on Tik is tcp based, and if tcp connection is run through the tunnel, that might cause some (unnecessary) retransmissions.

4

imho, just ignored it

i think, it’s because your connection not stable

5

Well to be hones I haven’t tried to see if it will log the same error during some kind of transfer for example. For now it’s logging it every time when a new connection is created to the server. I’d guess that it’s logging it before the tunnel is up as it is at the beginning of the connection. The thing that bothers me most is that it echo in the terminal and I’m seeing there this long string which I’ve posted in the first comment.

Otherwise I’d say that it’s pretty standard configuration - CA->Server->Client->vpn-pool->dhcp->ppp profile → secret. Something strange that I’ve come to is that I don’t have access to the router from the VPN client even when I have access to the server behind it. I’m yet to observe this problem but I was seriously disturbed by this dropping error.

6

Most people running ovpn on MT have this error. Nobody knows why or how to fix it. Only how to hide it in logs.
So your setup is OK.
I have it on all MT routers I am running or tested ovpn on.
Please stop responding if you have no input on the matter just to say “i think, it’s because your connection not stable”

7

Thanks for the information. In this case I’ll just search for a solution to hide the echo message in the terminal as it’s really annoying. I could also consider l2tp/ipsec but for now I’d like to stick ot OVPN as the most secure way.

8

Could you please advice how to hide it at least at the terminal as I could not find a way to hide the echo (except disabling all critical echo) I officially surrendered to seek for options to solve the problem with the error (probably I could test it on another mikrotik device) I had even idea to write to mikrotik support but I’m not sure if they’ll answer.

9

i have this problem on v6.46.7

10

anyone solved this problem ???

11

I have the same problem. Client send PushRequests but without PushReply from router. So client repeats the same PushRequest (maybee more times) until PushResponse is finnally received. So its logged as duplicate packed in routeros. Strange is that it works in android openvpn client for me, but only windows client has this problem.

12

fyi, “Openvpn connect” client don’t call such error in Mikrotik logs and also much faster bringing up TAP interface than “OpenVPN community” client.

Tried on Win10, macOS Big Sur

13

hello the same thing happens to me and the conclusion is that it happens to me when I activate the ovpn and I have a load balancing in pcc and I tried the ovpn in another mikrotik without balancing and it works but I have two with balancing and nothing does not work


how should I create the rule to route that vpn input

14

Hi everyone, I’m new here on the forum.
I ran into this same problem this week, using the latest version of the OpenVPN client (OpenVPN-2.6.3-I003).
I did everything but the error persisted.
I had the urge to test with previous versions, and to my surprise, with the version (OpenVPN-2.5.8-I604) everything worked perfectly.
Given the above, here is a tip to consider not using the most recent versions, as unfortunately there may still be some bugs that have not been properly corrected.
Hope this answer can be helpful.
Hug!

15

Hello, I have installed OpenVPN-2.5.9 client and worked fine. Thank you.