I want to chnage my zimbra's default webmail port from 80 to 81
I read wiki and forum lots and do following changes

su - zimbra
zmprov ms mail.mydomain.com zimbraMailPort 81
but zmprov getallconfig | grep zimbraMailPort still showing old port
zimbraMailPort: 80

so run /opt/zimbra/bin/zmprov mcf zimbraMailPort 81 command
now it is showing zimbraMailPort: 81
then do zmcontrol stop; zmcontrol start
but still webmail is opening on default port 80

so how can i change zimbra webmail's default port 80 to another port 81