Re: ftp problems pc to i5 at v5r3

[Scott Klement <midrange-l@xxxxxxxxxxxxxxxx>]

> You are correct and Scott was a little strong on his opinion there.  While it 
> is not REQuIRED to have your systems name and IP address in it's own host 
> table for things to work correctly it is usually the case.  The only time it 
> works well NOT to have the name in there is if DNS is set up to inlclude the 
> proper entries. Servers such as *SMTP *MGTC *HTTP(ADMIN) and others need to 
> know that the name being used resolves an IP address that is on the system. 
> Without this, "Unpredictable (but predictably bad) results will occur."

I can see why that would be needed for e-mail. The other thing it might 
be useful for is verifying digital certificates. I don't see why you'd 
need it for HTTP or MGTC.

But frankly, if you're using the HOST TABLE to verify digital 
certificates, or route e-mail, something is very wrong.

With e-mail, it means that you have to define every mail server and 
destination system in your host table for the entire world. And keep it up 
to date!  Why wouldn't you just set up DNS?

For digital certificates, what you're doing is bypassing the security 
checks. It's not REALLY validating the certificate, because you could set 
any value you wanted in the host table whether it's correct or not. It 
would be more of a workaround to avoid proper validation than anything 
else.

I maintain that it's a very bad idea.

Also, none of this relates to FTP, which was the question. When FTP data 
channels are established, it's the IP address that's sent with the PORT 
command, or as a response to the PASV command.  Not the domain name.  So 
DNS/HOST lookup will NOT cause a data channel connection to fail -- which 
is clearly what's failing.