topic Re: FTD 6.5 and Diffie Hellman G5 in Network Security

FTD 6.5 and Diffie Hellman G5

benolyndav — Mon, 10 Aug 2020 07:56:41 GMT

We have upgraded our soon to go live FTD's/FMC to 6.5 I have just seen a warning saying that DH group 5 is depreciated, does this mean that it just wont work as we have exsisting VPN's using DH group 5 on our current live devices ASA's

Thanks

Re: FTD 6.5 and Diffie Hellman G5

Rob Ingram — Mon, 10 Aug 2020 08:08:57 GMT

Hi,
If you upgrade to a newer version once DH group 5 has been depreciated, at that point you will have a problem. You should probably change your existing VPNs now, as DH group 5 is insecure - also avoid DH group 2 and 24.

HTH

Re: FTD 6.5 and Diffie Hellman G5

benolyndav — Mon, 10 Aug 2020 08:12:58 GMT

Hi Rob

Thanks for the quick response so are you saying DH 5 just wont work on 6.5 ??

Re: FTD 6.5 and Diffie Hellman G5

Rob Ingram — Mon, 10 Aug 2020 08:14:48 GMT

Hi,
No, I am saying it will currently work on 6.5.....but at somepoint in the future cisco will remove DH group 5, so don't upgrade until you've changed your existing VPNs.

Re: FTD 6.5 and Diffie Hellman G5

benolyndav — Mon, 10 Aug 2020 09:01:27 GMT

Thanks Rob