LB Exchange 2013 password prompt

Hi all,

We had configured F5 4000 s as a load balancer for exchange 2013 sp1 and LB is working fine, But the problem was when any of Exchange CAS server had fail-over, then connected outlook clients (outlook 2010) are prompting username/password, when username/password entered then outlook client getting connected with next available exchange CAS server.

• How to rectifies this issue ?
• When Googleing i found in KEMP LB they using session cookie to maintain session without re-authenticate when CAS fail over.In F5 how to fix this issue.

Pls suggest us and guide us.

Regards, Mariappan S