Blast, completely overlooked the external IP issue.
As for which Exchange services, does this help?
Code:
[PS] C:\Windows\system32>Get-Service | Where {$_.Name -match "Exchange"}
Status Name DisplayName
------ ---- -----------
Running MSExchangeADTop... Microsoft Exchange Active Directory...
Running MSExchangeAntis... Microsoft Exchange Anti-spam Update
Stopped MSExchangeEdgeSync Microsoft Exchange EdgeSync
Running MSExchangeFDS Microsoft Exchange File Distribution
Stopped MSExchangeImap4 Microsoft Exchange IMAP4
Running MSExchangeIS Microsoft Exchange Information Store
Running MSExchangeMailb... Microsoft Exchange Mailbox Assistants
Running MSExchangeMailS... Microsoft Exchange Mail Submission
Stopped MSExchangeMonit... Microsoft Exchange Monitoring
Stopped MSExchangePop3 Microsoft Exchange POP3
Running MSExchangeRepl Microsoft Exchange Replication Service
Running MSExchangeSA Microsoft Exchange System Attendant
Running MSExchangeSearch Microsoft Exchange Search Indexer
Running MSExchangeServi... Microsoft Exchange Service Host
Running MSExchangeTrans... Microsoft Exchange Transport
Running MSExchangeTrans... Microsoft Exchange Transport Log Se...
Running msftesql-Exchange Microsoft Search (Exchange)
Stopped wsbexchange Microsoft Exchange Server Extension...
I can do SBS, what I can't do is Exchange, so I appreciate any help you can offer, thank you.