Large drop in download bandwidth when using VPN. Anything can be done?

[Tintin]

Hi!

I know there has been a few posts about this before and I understand there will be some throughput loss when connected to the VPN – I just think what I'm seeing is a bit much.

For example, on a Wi-Fi with a 100 Mb/s theoretical connection I yesterday got 82 Mbps on the website fast.com which after connecting to our VPN yielded a drop to 22 Mbps. Isn't that a bit much or is this drop to be expected? Anything that can be done?

Hardware is MX 100 with firmware MX 17.10.4

[alemabrahao]

Have you tried disabling the option "Use default gateway on remote network"?

[Tintin]

Forgot to mention I in the above test used the Cisco Secure Client application and operating system MacOS Ventura 13.2.1


So thanks @alemabrahao, but no; I haven't tried that. I think ”Use default gateway on remote network” is an option in Windows, right?

[alemabrahao]

So are using the Anyconnect Client VPN right? Are you using split tunneling?

[Tintin]

Yes, AnyConnect VPN is what it says when I open the Cisco Secure Client.app

Setup like this in the AnyConnect Settings in Meraki:

[alemabrahao]

Try specifying the destination traffic only for your LAN networks to validate if it will make any difference.

[Tintin]

OK, thanks. But not sure how to do that. ”Only send traffic going to these hostnames” and adding the details for our LAN?

Do I do it for both ”Client Routing” and ”Dynamic Client Routing”?

[alemabrahao]

Take a look on the documentation.

https://documentation.meraki.com/MX/Client_VPN/AnyConnect_on_the_MX_Appliance#Client_Routing

[Tintin]

A bit unsure how to set it up. If I just need VPN tunneling to a few specific IP addresses on our LAN, how do I specify that? Would that help with performance instead of routing all traffic via the VPN (I guess it would)?

Sorry for my ignorance and thanks for the help!

[PhilipDAth]

As @alemabrahao says - enable split tunneling on AnyConnect.