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SFTP and Stateful Firewalls

Hi,

So I have an internal server that will be automatically grabbing files from an external FTP server via SFTP. It will be going through a stateful firewall. I was able to configure it with the help of a coworker, but I am trying to get an understanding of how a stateful firewall can cause difficulties in an SFTP connection. Is it dumb to say that SFTP = encrypted port 21 traffic ? Any helpful explanation or URLs to resources would be appreciated. Google was not being very helpful.

Thanks

svgmuc

Actually, SFTP should be encrypted traffic on port 22, if not chosen differently.
Usually, SFTP uses SSH as an encrypted layer, which usually is on port 22.

Elemental12

ASKER

I understood that part. I just need some background about it's interaction with a stateful firewall, and some of the possible issues that can occur.

deisrobinson

For clarity:

1. SFTP - simple file sharing protocol
2. sFTP - Secure File transfer protocol (Uses SSH/SCP commands)
3. FTPs - File transfer protocol over SSL (Uses FTP commands NO SSH here)

Now take a look here:

http://en.wikipedia.org/wiki/Stateful_firewall

This explains what the stateful firewall is and how it works. After taking the previously stated into consideration andt he actual type of protocol you are using you can see where some packets would be filtered out. BUT this should affect any kind of un secured traffic.

Elemental12

ASKER

Thank you for the article. So my question then becomes if a user names an sFTP connection outbound through the firewall, stateful inspection running on the firewall would require that the return traffic be on the exact same port number?

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deisrobinson

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Elemental12

ASKER

Thank you very much, I appreciate the assistace.