Accessing Exchange 2013 via NetScaler is significantly slower than going directly to backend servers. There are timeouts and latency reported.

Primary Recommendation:

• Disable surge protection on all related Exchange services/service groups. Services > Settings > Surge Protection = Disabled/OFF

• Ensure source IP persistence is enabled for all related Exchange Vservers with a timeout value of more than 2 minutes. (60 minutes or 120 minutes)
• Internal Vserver - Change source IP persistence timeout value from 2 minutes to 60 minutes/120 minutes
• External Vserver - Enable source IP persistence and change timeout value to 60 minutes/120 minutes
• Increase client idle timeout on related Exchange Vservers from 180 seconds to at least 1800 seconds. (1800/3000 should be fine). (Vserver > Traffic Settings > Client Idle Timeout)
• Increase client and server idle timeouts on services from 180/360 to 1800 or 3000 seconds. (Service > Thresholds and Timeouts)

Problem Cause

Surge Protection was enabled on the service causing Surge Queue build-up on the Exchange services. Disabling surge protection fixed the issue.