|Ah, it sounds like it entirely depends on how your credentials are handled, your description doesn't mean much on that light unfortunately.
Regardless, there is definitely a firewall between you and the internal network that you don't have to contend with while on site. I suspect it will boil down to how authentication is handled. If possible, I've found the easiest solution is to use a jump box or terminal server to work from on premises.
"There are three kinds of lies: lies, damned lies and statistics."
- Benjamin Disraeli