F5 Load Balancing Exchange 2013

Well...in our testing environment under my Pool profile, I made two adjustments “Action on Service Down=REJECT”, and “Slow Ramp Time=300 seconds”…..I’m currently pending my exchange team to test in the test environment, as of today they haven’t tested yet. But I came to this solution from talking to F5 tech-support F5 tech-support solution: When the server is shut down, F5 Exchange pool is currently set to: 'do nothing' and that is what it does.

Please change the setting for the pool to 'reject'. Per the F5 iapp deployment guide, this is the recommended setting.

Pools (Main tab > Local Traffic > Pools) Health monitor Add health monitor above.

Action on Service Down Reject Slow Ramp Time 300

Load Balancing Method Least Connections (member) recommended

Address IP Address of Client Access server running RPC Client Access

Service Port * All Services (repeat Address and Port for all members)

https://www.f5.com/pdf/deployment-guides/microsoft-exchange-iapp-dg.pdf

! Then my response: Interesting.........after you pointed that out in your original e-mail I would have guess "Reselect" would be the best choice, but the recommend option is "Reject"....any idea why "Reject" is a better option?

! F5 tech-support response: In this specific case, (MS exchange 2013) I cannot explain why Microsoft choose 'reject' instead of 'reselect.' The iApp guide does not explain their thinking. But this was written in concert between Bigip and MS and is the recommended practice.

In general what will happen if that pool member is down, the system will send new connections to the active pool member and for existing connections that point to the down pool member the connections are reset but no RST is sent to the client can reconnect.

Reject: Specifies that, if there are no pool members available, the system resets and clears the active connections from the connection table and sends a reset (RST) or Internet Control Message Protocol (ICMP) message. If there are pool members available, the system resets and clears the active connections, but sends newly arriving connections to the available pool member and does not send RST or ICMP messages.

Reselect: Specifies that the system manages established client connections by moving them to an alternative pool member when monitors mark the original pool member down.

Hope this helps!!!!! KDS