Now that I've really started looking for this, I'm quite sure that push is not working on the lan. Here's the config.
DNS A record entry for mail.domain.com to public IP at the domain registrar
MX record to mail.domain.com and the registrar
DNS A record on internal DNS for mail.domain.com to internal IP of zimbra server
MX record on internal DNS to mail.domain.com
Ping mail.domain.com from home and it resolves to the public IP, ping the same name from the computers in work, or the work wifi and it resolves to the internal IP, this is what I'd expect to happen.
A user here had wifi disabled on his phone (no wifi at home) and push worked fine for him. As a test, we enabled the wifi on it so it would connect the the local lan and push stopped working.
The DHCP server onsite sends out IP addresses for the two DNS servers we have onsite here, both windows active directory servers.
I have another installation exhibiting the same symptoms where the only infrastructure difference is a BIND server running on ubuntu instead of the windows DNS.  |