Posted: Tue Mar 05, 2024 14:23 Post subject: OpenVPN MTU setting
Hi all, I am having issues with MTU settings in my VPN config.
My setup is made of two WRT1200ACv2 running 51362, both of them are behind the provider's router. I have made some ping tests directly on the provider's router to check the MTU, which is 1464, as from 1465 I get packet loss.
I set that value in the server/client MTU settings but it is not working well at all. I have noticed that setting the values to 1420 helps, but still not the best working configuration.
I remember there is some other OpenVPN data to consider in the MTU settings, so maybe that's why 1464 is not working. Any maths that needs to be done to subtract from 1464 a specific value?
Should I use Tunnel UDP Fragment or Tunnel UDP MSS Fix?
I went through several guide versions for OpenVPN configurations here on the forum, but I couldn't find what I need.
Any reason for running such an old build? _________________ "The woods are lovely, dark and deep,
But I have promises to keep,
And miles to go before I sleep,
And miles to go before I sleep." - Robert Frost
"I am one of the noticeable ones - notice me" - Dale Frances McKenzie Bozzio
Joined: 16 Nov 2015 Posts: 6447 Location: UK, London, just across the river..
Posted: Tue Mar 05, 2024 16:18 Post subject:
yep quite old build 14-15 months old..lots of vital updates and fix's...current build 55262...
default OpenVPN MTU value is 1400 or less...must be in the guide...
better update anyway...
"Should I use Tunnel UDP Fragment or Tunnel UDP MSS Fix?" -- no _________________ Atheros
TP-Link WR740Nv1 ---DD-WRT 55630 WAP
TP-Link WR1043NDv2 -DD-WRT 55723 Gateway/DoT,Forced DNS,Ad-Block,Firewall,x4VLAN,VPN
TP-Link WR1043NDv2 -Gargoyle OS 1.15.x AP,DNS,QoS,Quotas
Qualcomm-Atheros
Netgear XR500 --DD-WRT 55779 Gateway/DoH,Forced DNS,AP Isolation,4VLAN,Ad-Block,Firewall,Vanilla
Netgear R7800 --DD-WRT 55819 Gateway/DoT,AD-Block,Forced DNS,AP&Net Isolation,x3VLAN,Firewall,Vanilla
Netgear R9000 --DD-WRT 55779 Gateway/DoT,AD-Block,AP Isolation,Firewall,Forced DNS,x2VLAN,Vanilla
Broadcom
Netgear R7000 --DD-WRT 55460 Gateway/SmartDNS/DoH,AD-Block,Firewall,Forced DNS,x3VLAN,VPN
NOT USING 5Ghz ANYWHERE
------------------------------------------------------
Stubby DNS over TLS I DNSCrypt v2 by mac913
Thanks Alozaros. I’ll tell you what I have tested:
In first place I left the 0 “not set” value, that was not working so I switched to 1500, then manual 1400, then 1440, 1492 etc. I have tried many possible values, some goes better than others, but still not a fluid experience through the tunnel
