HI bacohen8
Some thoughts below.
A) Internally - create an alias url such as "helpdesk" and alias to the IP of the ServiceDesk. I find a lot of people put their ServiceDesk on servers such as stadnardapps001 etc and end users can't get to the portal
B) Externally - What most customers tend to do is create a subdomain e.g. servicedesk.company.com and point it to their public IP
C) Externally - I would put a reverse proxy in the way to give you some control over who can reach the servicedesk plus server.
D) If you are using VPNs for remote users then you don't need to worry about making the public subdomian.