While most academic domain validations proceed without issue, we've run into a few validation issues that may require some action on your end.
No reverse DNS information
If grbgetkey produces a message that looks like this...
ERROR: Unable to determine hostname for IP address 234.28.234.12....it means that your machine has no reverse DNS information. This usually happens when you are connecting to the Internet through a DHCP server that does NAT (network address translation) or PAT (port address translation), but does not provide DNS information for its clients. The simplest way to resolve this issue is to ask your network administrator to add a DNS entry (a PTR record, to be more specific) for the DHCP device itself.
Note that there is unfortunately no way for us to validate your academic license without reverse DNS information. You can visit this site to check DNS information for your IP address and to obtain for more information about reverse DNS.
Not a recognized academic domain
If grbgetkey produces a message that looks like this...
ERROR: your hostname (mymachine.mydomain) was not recognized as belonging to an academic domain....it means that your domain isn't on our academic domain list. Please make sure you are connected to your university network. If the reported host name is a valid university address, please send the specific error message you receive to support@gurobi.com and we'll add your domain.
Connecting to your academic domain through a VPN will typically not present a problem for validation, since the request will appear to originate from inside your academic domain. However, some VPNs are configured to use split tunneling, where traffic to public internet sites is routed through your ISP. Split tunneling introduces a major security hole into the private network, so it is not that common. If you find that your validation request is rejected when you are connected to your VPN, you should ask your network administrator whether the VPN can be configured to route traffic to gurobi.com through the private network.
Some machines connect to the internet through a proxy server. Unfortunately, such configurations are incompatible with our academic validation process.