Slow SMB Transfer (and everything else slow) over Global Protect VPN

[Remo]

Hi community

Do you also have issues with low transferrates over globalprotect VPN? And maybe already have a solution for this?

I tested the following setup

1. Client connected with GBit LAN to the internal network without VPN
2. Client connected with Gbit LAN to the GP gateway
3. Client connected to the internal network with MTU set to 1400 (like with GP) and Bandwidth limited with a WAN simulator to 200 Mbit and a delay of 6 ms in both directions
4. Client connected to the GP gateway with a Bandwidth of max 200 Mbit and a delay of 6 ms in both directions

Without Globalprotect my tests with iperf and SMB always show that every available bit of bandwith is used for the transfers. As soon as I am connected to Globalprotect the tranferrates drop - in some cases dramatically. The worst was with GP connected on the Gbit link. With SMB I was only able to copy (large) files with max 6 MByte/s.

Globalprotect version used is 5.0.5.

Any help is really appreciated!

Regards,

Remo

[jdelio]

Hey @Remo ,

Hate to hear whenever you have slow thruput with GP..  Do you have any restrictive policies in place? 

Can you test with an "Allow" policy and see if that changes anything? or do you think that the fact that the traffic has to traverse your work network to get anywhere is causing the slow thruput?

[Brandon_Wertz]

Could it be related to DSRI being enabled on the security rule the traffic is matching?

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClpfCAC 

https://live.paloaltonetworks.com/t5/General-Topics/Slowness-with-http-file-transfer-after-placing-P...

[jdelio]

Just incase anyone is interested, a Blog has been written to help with this topic here:

https://live.paloaltonetworks.com/t5/blogs/why-is-smb-traffic-slow/bc-p/357967

Be sure to check it out.