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uni's avatar
uni
Icon for Altostratus rankAltostratus
Mar 20, 2014

Best practice for clientssl profiles

Can anyone recommend their preferred settings for clientssl profiles? What cipher string, options and other flags do you use?   I usually test mine using , but get at best an "A-".  
application delivery
design
LTM
security
TMOS
OTS02's avatar
OTS02
Icon for Cirrus rankCirrus
Jan 20, 2015

Just updated LTMs to 11.6.0 HF3, and that seems to automatically get you an A-. Seems Qualys SSL Labs wants you to emphasize Perfect Forward Secrecy, to get the full "A". After a lot of trial & error in a test SSL client profile (with default clientssl as parent), I managed to get an "A" by using this:

 

ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-CBC-SHA:ECDHE-RSA-AES128-SHA256:ECDHE-RSA-DES-CBC3-SHA:ECDHE-RSA-DES-CBC3-SHA:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES256-CBC-SHA:DHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA:DHE-RSA-DES-CBC3-SHA:AES128-SHA256:DES-CBC3-SHA:!SSLv3

 

The only other thing not default, was checking the "Strict Resume" box. The only browser that is incompatible is IE 6/XP.

 

I have yet to test this for any speed penalties (PFC is said to be slower).