LAN Printers are killing OpenVPN - Maybe

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pigeon35
OpenVpn Newbie
Posts: 2
Joined: Sat Dec 04, 2021 5:04 am

LAN Printers are killing OpenVPN - Maybe

Post by pigeon35 » Thu Dec 23, 2021 10:18 pm

Hello,

I've spent weeks tweaking MTU, MSSFIX and missed something from the start. The dropouts are regular.
But what is going on? Hoping you can advise please.

Windows 10 Pro 21H2 OpenVPN 2.5.4 Server + Clients.

Server = Xeon E3-1270 V2 @ 3.50GHz (4 core, 8 thread) + 16GB RAM

Same issue if 1 user or 8

Remote Desktop session to VPN server dies ever 30mins around 21 past the hour and 51 past the hour +/- 3 seconds.

Seems to stem each time from this, a printer
7779 21:51:36.893377 192.168.160.9 192.168.160.10 TCP 66 0xc672 (50802)
Ethernet 51923 → 80 [SYN] Seq=0 Win=64240 Len=0 MSS=1460 WS=256 SACK_PERM=1

The next hour it will be 192.168.160.117, another printer.

Remote LAN = 192.168.160.0/24
VPN Server = 192.168.160.9 LAN (10.8.1.1 VPN Server)
Home LAN = 192.168.1.0/24
Home VPN Client = 10.8.1.2


Wireshark home Wifi+OpenVPNtun, destination unreachable when pings start to fail

Image



Wireshark remote 1gb ethernet+OpenVPNtun server, light green line seems to be trigger

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Remote, and again an hour later. Pings at home fail, remote has TCP Retransmission on RDP.
Dark green line possible trigger

Image


Has anyone seen this before? Any suggestions as to what is happening and how to fix it would be fantastic!

Thank you.

TinCanTech
OpenVPN Protagonist
Posts: 11137
Joined: Fri Jun 03, 2016 1:17 pm

Re: LAN Printers are killing OpenVPN - Maybe

Post by TinCanTech » Fri Dec 24, 2021 9:17 pm

pigeon35 wrote:
Thu Dec 23, 2021 10:18 pm
Remote Desktop session to VPN server dies ever 30mins around 21 past the hour and 51 past the hour +/- 3 seconds.

Seems to stem each time from this, a printer
So, you have a rogue-like printer which is hacking your network ? Sounds like a new player-class for nethack.

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