External FTP access on custom port

I am trying to set up FTP access for external users.  Naturally, I don't want to open Port 21 to the outside world so I began by creating a firewall rule to forward a custom port 2100 to the server, translating it to 21.  When that failed I changed the listening port in IIS to 2100.  Internally I can access the FTP no problem with:
When I try to access externally however I get a timeout.
If I change the listening port on the server (and the firewall rule) to 21 it works.
When I have everything set to 2100 I'm getting to the server- but this is what I get in the FTP log:

15:14:34 [17]USER receptionist 331 0
15:14:34 [17]PASS - 230 0
15:14:34 [17]CWD / 250 0

So- what else do I need to change to allow the custom port?
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Jaroslav MrazCTOCommented:
Firewall in server and try pasiv mode in client
STS-TechAuthor Commented:
Firewall is disabled on server- but I added an exclusion for port 2100 just to be on the safe side.  Passive mode was already enabled in IE, but tried turning it off- same result.  Also tried opening in Windows Explorer- same thing.
STS-TechAuthor Commented:
I'm using the following to connect:

Should I be doing something different?
10 Tips to Protect Your Business from Ransomware

Did you know that ransomware is the most widespread, destructive malware in the world today? It accounts for 39% of all security breaches, with ransomware gangsters projected to make $11.5B in profits from online extortion by 2019.

Jaroslav MrazCTOCommented:
Hmm sometimes is problem IE try fiezilla its free client IP without '

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
STS-TechAuthor Commented:
Results from Filezilla:

Response:      230 User receptionist logged in.
Command:      SYST
Response:      215 Windows_NT
Command:      FEAT
Response:      211-Extended features supported:
Response:       SIZE
Response:       MDTM
Response:      211 END
Status:      Server does not support non-ASCII characters.
Status:      Connected
Status:      Retrieving directory listing...
Command:      PWD
Response:      257 "/" is current directory.
Command:      TYPE I
Response:      200 Type set to I.
Command:      PASV
Response:      227 Entering Passive Mode (192,168,10,2,199,48).
Status:      Server sent passive reply with unroutable address. Using server address instead.
Command:      LIST
Response:      425 Can't open data connection.
Error:      Failed to retrieve directory listing
STS-TechAuthor Commented:
"Fixed" it.  Installed Filezilla server, this allowed me to set a range of ports to be used by passive mode.  Added those ports to the Custom FTP service in the firewall and I'm in.  Not really a true fix as I'd rather use IIS, but the results are the same for the end users.

Thanks for pointing me in the right direction with FZ!
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Internet Protocols

From novice to tech pro — start learning today.