http://www.dslreports.com/faq/10283
Does Telus block any ports?
Yes Telus currently does block ports to users on home and Office packages.
The only packages with no blocked ports at this time are the Server packages.
The Blocked ports currently are:
TCP 21 (ftp)
Customers running an FTP server will no longer be able to have Internet users connect to their server. Many customers computers are used as FTP servers to store illegal files.
TCP 25 (smtp)
Customers running a SMTP mail server will no longer be able to receive email requests. Also, Telus users will not be able to connect to non-Telus smtp servers on port 25. Prevent mail servers that operate as an open relay. Open relays are used without a customer?s knowledge to sends millions of pieces of Spam.
TCP 80 (www)
Customers running a Web server will no longer be able to have Internet users connect to their server. Common exploit on old Window IIS server and Linux boxes that are not properly patched.
TCP 110 (pop3)
Customers running a POP mail server will no longer be able to have Internet users connect to the server. Prevent mail servers that operate as an open relay. Open relays are used without a customer?s knowledge to sends millions of pieces of Spam.
TCP 6667 (ircd)
Customers running a IRC server (Internet Relay Chat) will no longer be able to have Internet users connect to the server.
TCP/UDP 135-139 (dcom and netbios)
These ports are commonly exploited by worm viruses:
135 Windows RPC
136 PROFILE Naming System (basically unused)
137-139 Windows NetBios
TCP/UDP 443 (ssl)
TCP/UDP 445 (ms-ds)
Microsoft Directory Services - Customers that allow legitimate Internet users access to their computers will loose this ability. This allows hackers to directly connect to a Windows based computer and gain total control over the OS.
TCP/UDP 1433-1434 (ms-sql)
Microsoft SQL server - Customer running an SQL server will no long be able to have Internet user connect to their server. There are several worm viruses that exploit holes in SQL server.
