mysql can't get hostname for your address

Solution 1:

When you say the client in question

is able to connect without any problems from Home network but not from his work network

then I assume it will get assigned a different IP address when connected to the office network versus when connected via VPN from home.

Getting a hostname for an address is nothing but reverse DNS, i.e. first of all, find out which IP address the machine is assigned in the office network and in the home network, see: https://apple.stackexchange.com/questions/20547/how-do-i-find-my-ip-address-from-the-command-line.

Then try an

nslookup

using either address and check if a hostname is being reported or not. I'd bet in case of the office network, it will come back with NXDOMAIN.

Then the next question is why. That means you will have to check how IP is resolved to names on your network. This can either be a local hosts file or some DHCP/DNS server on your network which doesn't know the name for an IP it's given out.