Writing up a report for a PITA client right now. I swear I hate being subcontracted out. I could write a literal book on all the things that went wrong while trying to get started with these guys, but that's another story for another day.
Classic environment, but they actually did a good job locking things down. Found an on-prem AD server that also had SQL Server running (port exposed), but when I went back to do some more recon, the entire server is locked out. Only SSH access, so go figure. Thankfully I had previous scans for it, but still.
My suspicion is that someone firewalled it off. That's fine, I'm not going to bitch about it, but I will tell them about the finding. I doubt I'll come back to them in the future, but I'll be damned if I lose an ounce of sleep over this.