[Xitami] Xitami FTP port.

[xitami@lists.xitami.org]

Hello Brian,


THANKS for your reponse! :)


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>.
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>.
> >         2. If so and port 20 is used by Xitami should it 
> >            be discussed in the documentation?
> 

OK and I apologize that I did not mention that a ROUTER with the NAT firewall is involved.
And, you answered that issue below. 


> Why should it?  Port 20/21 is part and parcel of FTP, which was
> standardized in RFC-765 way back in June of 1980.
> 
> It's only things like firewalls and NATted routers which cause difficulty
> with this standard, and it is in that area that further documentation
> ought to be expected.
> 

Yep,,,,,,EXACTLY!

So, for those that are not completely up-to date with respect to these issues, etc. it would have been helpful if this had been discussed in the documentation along side the description of Port 21. As a result, it took some time away from others who very graciously responded to and helped solve this issue of Xitami FTP Server related to a ROUTER.


Regards,

Jerry




> In message 
> <051020041639.7881.409FB03C000836C600001EC92160376021FFCC9891909398@att.net>
>    jglong3@att.net writes:
> 
> > The following was listed at IANA for ports 20 and 21;
> > 
> >       ftp-data         20/tcp    File Transfer [Default Data]
> >       ftp-data         20/udp    File Transfer [Default Data]
> >       ftp              21/tcp    File Transfer [Control]
> >       ftp              21/udp    File Transfer [Control]
> > 
> > Please forgive me, the last time I worked with any level of protocol
> > was a long time ago (circa "IBM BI-SYNC" and previous).
> > 
> > It does look like port 21 is to logon with username:password control
> > (authentication???) and that 20 would be the up/down load of files(???).
> > 
> > 
> >         1. Is this the meaning for port 20 and 21? 
> 
> Yes: port 21 is used for control connections (of course, the originating
> FTP client can use anything it likes).  Port 20 is used, by an FTP
> server, for uploaded [i.e. PUT] data; in the full protocol, downloaded
> [i.e. GET] data is sent TO whichever port the client has negotiated with
> a PORT command, from port 20 on the server.
> 
> >         2. If so and port 20 is used by Xitami should it 
> >            be discussed in the documentation?
> 
> Why should it?  Port 20/21 is part and parcel of FTP, which was
> standardized in RFC-765 way back in June of 1980.
> 
> It's only things like firewalls and NATted routers which cause difficulty
> with this standard, and it is in that area that further documentation
> ought to be expected.
> 
> RFC-765 includes a rather useful bit of "ASCII Art":
> 
>                                             -------------
>                                             |/---------\|
>                                             ||   User  ||    --------
>                                             ||Interface|<--->| User |
>                                             |\----:----/|    --------
>                   ----------                |     V     |
>                   |/------\|  FTP Commands  |/---------\|
>                   ||Server|<---------------->|   User  ||
>                   ||  PI  ||   FTP Replies  ||    PI   ||
>                   |\--:---/|                |\----:----/|
>                   |   V    |                |     V     |
>       --------    |/------\|      Data      |/---------\|    --------
>       | File |<--->|Server|<---------------->|  User   |<--->| File |
>       |System|    || DTP  ||   Connection   ||   DTP   ||    |System|
>       --------    |\------/|                |\---------/|    --------
>                   ----------                -------------
> 
>                   Server-FTP                   User-FTP
> 
>       NOTES: 1. The data connection may be used in either direction.
>              2. The data connection need not exist all of the time.
> 
>                       Figure 1  Model for FTP Use
> 
> PI = Protocol Interpreter; DTP = Data Transfer Port.
> 
> -- 
>    fix (vb.): 1. to paper over, obscure, hide from public view; 2. to
>    work around, in a way that produces unintended consequences that are
>    worse than the original problem.  Usage: "Windows ME fixes many of the
>    shortcomings of Windows 98 SE".
> 
> 
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