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VPN - connection speed reduces by 50%

When I connect VPN, my connection speed reduces by 50%. I know several people with the same problem. Has anyone else noticed this? I have two servers in my company, they are on the same network. One is accessible via the Internet. In them I hosted a test file with a size of 200 MB. When I download via Internet the rate is 4.2 MB/s; when I go down via VPN the rate goes to 2.2 MB/s.

Details: S.O.: Windows 10
Client Version: E80.70 build 986001031

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13 Replies
Admin
Admin

Re: VPN - connection speed reduces by 50%

A few things:

1. Why are you posting your message text as "preformatted" in this case? It makes your post hard to read since the text must be scrolled. There is no need to format this particular text.

2. When your say your connection speed drops by 50%, how are you measuring this and to what sites? Are they sites reachable via the VPN or? Because, yes, VPNs have overhead to them and, if you're measuring throughput to a given site when connecting to a VPN versus not, it's going to be slower due to the encryption and packet overhead. Will it be 50% slower? Depends on the circumstances.

3. We also need some very basic details such as OS version, client version, and what gateway you are connecting to.

Re: VPN - connection speed reduces by 50%

Thanks for the feedback, I've edited my question.

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Admin
Admin

Re: VPN - connection speed reduces by 50%

Any file transfer over a VPN is going to be slower than when you don't use a VPN.

This is because:

  • Encryption and decryption takes additional CPU overhead on both endpoints.
  • The original, unencrypted traffic is encapsulated in new packets, which means to transfer the same amount of effective data, more bits must be transmitted across the wire.
    • VPN encapsulation can also have impacts on the underlying application used to transfer the file due to the changes in packet sizes, causing additional packets to be necessary.

Is it going to be 50% slower?

It depends on a lot of factors, but it doesn't seem out of the question, especially given the transfer speeds you're talking about. 

Re: VPN - connection speed reduces by 50%

Thank you for your consideration. The fact is that I have friends who use the same solution, including the same Internet service provider, without slowing down. Intriguing, is not it? Can you do a similar test?

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Admin
Admin

Re: VPN - connection speed reduces by 50%

Your friends could easily be seeing better results because:

  • They have a different PC with different software loaded on it
  • They are using a different modem and router
  • The same ISP in their location performs better than it does yours

And that doesn't even begin to factor in what might be happening on the server end.

Without understanding the complete end-to-end picture, it's hard to say what is causing the difference in performance.

Further, without a complete understanding of those details, any test I might do would be unlikely to produce a meaningful result.

It's possible the TAC may be able to help you troubleshoot what's going on.

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Re: VPN - connection speed reduces by 50%

We use the same notebook model provided by the company, without access to changes in the software. We use the same broadband provider, same router model, we are in the same city.

TAC? I did not understand.

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Admin
Admin

Re: VPN - connection speed reduces by 50%

Even the same ISP in different physical locations within the same city can have different performance characteristics.

Wired versus wireless connections can make a difference.

There are a lot of variables you need to eliminate as potential sources.

TAC, as in our support: Contact Support | Check Point Software 

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Re: VPN - connection speed reduces by 50%

It should have no relation to these location or route variables. The problem always happens when I connect via VPN. When I use out of VPN the rate goes up again.

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dggdmn
Ivory

Re: VPN - connection speed reduces by 50%

Hi,

Did you find a solution to the 50% drop in speed.  I have the same problem.

 

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dggdmn
Ivory

Re: VPN - connection speed reduces by 50%

Has solution to the problem been found?

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Re: VPN - connection speed reduces by 50%

When you make sure to use AES-128 or 256 encryption, this should be handled by hardware which is part of most of the later cpu's .
Regards, Maarten
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dggdmn
Ivory

Re: VPN - connection speed reduces by 50%

Would encryption cause a 50% drop?  Can a Checkpoint appliance restrict the amount of bandwidth each user is allowed?

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Re: VPN - connection speed reduces by 50%

You have a sub-1500 MTU somewhere between the VPN client and firewall, which is causing packet loss since IPSec traffic cannot be fragmented in transit (has the DF bit set).  TCP eventually throttles down far enough such that everything fits without fragmentation, until it tries to speed back up at which point the packet loss returns.  TCP yo-yo's up and down at the low MTU size threshold with lots of packet loss and bad performance.  Look into TCP MSS clamping or force your transport protocol from IPSec to HTTPS/TLS if possible.  You can also try lowering the MTU on your Windows 10 NIC to 1400 but that may not necessarily fix the problem in both directions.

Also make sure you are using AES not 3DES for your encryption protocol as that will reduce the load on the firewall; not sure if using 3DES would be the sole cause of a 50% drop in performance but I guess it could if the firewall is already heavily loaded.

 

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