Will a change to the Sonicwall TZ170 GroupVPN settings permanently disconnect existing users

Paul_Olson used Ask the Experts™
I have 'inherited' an existing Sonicwall TZ-170.  The device is currently serving a number of remote clients (Windows clients using the Sonicwall VPN client, and a Mac using some third-party tunnel application) and there is one site-to-site VPN path to a remote network.  All is working well at this point.  I am trying to allow / make it possible for some Linux-based workstations to use the VPN as a client (using vpnc from SUSE and UBUNTU clients) much the same as the Windows clients currently do.  When they connect, they get an error '(ISAKMP_N_INVALID_EXCHANGE_TYPE)(7)'.  The information I have read from some Internet digging indicates that I need to set up the groupVPN to use Diffie-Hellman group 5 as the DH group.  I am using DH Group 2 in the configuration at this point.

My question is:  Can I make this change (from DH 2 to DH 5) without affecting the existing VPN clients?  I am not sure of the impact of this change, and it is not clear to me that I can change it to group 5, test, and then change it back to group 2 if it does not work.  Is the DH setting for the groupVPN something that I can change on the Sonicwall device without affecting the clients and the site-to-site VPN?  A follow-up question would be if there exists some information on connecting a Linux workstation to a Sonicwall GroupVPN.
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Distinguished Expert 2017
Changing a setting on the Sonicwall will affect all users.
Alternatively, you could create a new VPN policy that will handle the linux vpnclient.
i.e. vpn policy 1 deals with teh windows
vpn policy 2 deals with the macs
vpn policy 3 is site-to-site
vpn policy 4 linux vpn remote setup.

Double check the policy you set on the linux client to use the DH 2 group versus the DH 5.
The client might default to DH 5 if not set, but could be set to DH 2.

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