Category Archives: KEMP Loadbalancer

Mobile phone battery drain with Kemp Loadbalancer

Recently I implemented two KEMP LM2600 at customer site (Exchange 2013 CU3 multi role servers). At the next day customers help desk got a lot of user complaints because battery life time of their mobile phones was reduced dramatically (iPhones using EAS – Exchange Active Sync)

Solution: In Network Options uncheck “Enable TCP Keepalives”

Kemp Keepalives

Kemp documentation is recommending this as well

Enable TCP Keepalives
By default the TCP keepalives are enabled which improves the reliability of TCP connections that are long lived (SSH sessions). Keepalives are not usually required for normal HTTP/HTTP Services. The keepalive messages are sent from the LoadMaster to the Real Server and to the client. Therefore, if the client is on a mobile network, there may be an issue with additional data traffic.

My comment: At the end of the day I am asking why this setting is active per default? And why this can not be set for each VS – Virtual Service? Be aware that this is a global configuration and it my affect other Services / Real Servers. To be honest, this was the first time of seeing such a behavior.

Kemp Loadmaster: Real Servers are local

Problem: Ever tried to treat some servers in your local IP Subnet exceptional in “non-transparent” Mode? OK, the solution for this ┬áis the function “real servers are local” BUT what to do if your Exchange Server Roles are separated and you need your Mailbox-Servers to work in non-transparent modus?

Solution: In your Kemp Configuration take your Mailbox-Servers into the VS (Virtual Service) and disable them. This will tell Kemp: Hey, I know them and I have to treat them as non-transparent.

Have Fun, Jimmy