Telus blocks you from hosting several services on your home internet connection. This prevents you from hosting things like web sites, ftp servers, mail servers, on their native ports. You can get around this by hosting these services on non-standard ports or using a VPN connection that doesn't block the same incoming traffic.
The rationale for blocking these services appears to be under the guise of protecting users and the Telus network from malware. Really it's just a way to prevent you from fully utilizing your home connection and to force you to buy a more expensive tier of service.
The only packages with no blocked ports at this time are the Server packages.
The blocked ports currently are:
TCP 21 (ftp)
TCP 25 (smtp)
Email delivery server (MTA - Mail Transfer Agent)
TCP 80 (www)
TCP 110 (pop3)
POP3 email retrieval servers (MDA - Mail Delivery Agent)
TCP 6667 (ircd)
IRC servers (Internet Relay Chat)
TCP/UDP 135-139 (dcom and netbios)
135 Windows RPC
136 PROFILE Naming System (basically unused)
137-139 Windows NetBios
TCP/UDP 443 (ssl)
Secure web browsing - HTTPS
TCP/UDP 445 (ms-ds)
TCP/UDP 1433-1434 (ms-sql)
Microsoft SQL Server