Problem in establishing FTP connection

[Vishal1 Kumar <vi...@aricent.com>]

Hi,

I am implementing a NAT enabled router for one of my client software.
[cid:image002.jpg@01CAFB32.AEAED370]

I am having problem in FTP data connection establishment when a router is in between my ftp-client and ftp-server which is NAT enabled.

The problem is, when I tried to make a data connection in active mode(port).

I have implemented following in my router s/w for active mode data-connection:
1) I NAted the port command of FTP header at my router software(in addition to the IP NATing). So in response the ftp-server responded me [200 PORT command successful].
     eg.
         actual  client Request command: PORT 192,168,255,241,14,42
         NATed client Request command: PORT 10,10,10,10,14,42
         Response received from server: 200 PORT command successful -> This response was forwarded to the client after required ip NATing.

2) Now when the ftp-client starts its data-connection with "STOR" command, my ftp-server responded back with [502: Syntax error, command unrecognized]
    One other ftp server responded in the same scenario with error response: [500: Command not implemented]

Now I checked all the check sum values in ip/tcp header; all seems fine. I am not able to track the exact problem even after performing the NAT required in FTP header to implement the active data mode connection.


Can you find where I did wrong; Or can you please refer any place to look?

Thanks in advance.


Thanks and Regards,
Vishal Kumar
Software Engineer
A R I C E N T


Electronic City, Plot 6

Sector - 18, Gurgaon 122015

Haryana, India

Extn: 7737
Mob no: +91 9717953693

"DIAMOND is just another piece of COAL that did well under PRESSURE."





________________________________
"DISCLAIMER: This message is proprietary to Aricent and is intended solely for the use of the individual to whom it is addressed. It may contain privileged or confidential information and should not be circulated or used for any purpose other than for what it is intended. If you have received this message in error, please notify the originator immediately. If you are not the intended recipient, you are notified that you are strictly prohibited from using, copying, altering, or disclosing the contents of this message. Aricent accepts no responsibility for loss or damage arising from the use of the information transmitted by this email including damage from virus."

Re: Problem in establishing FTP connection

[David Latorre <dv...@gmail.com>]

Is this using Apache FTPServer?

Is it possible that there's any syntax problem with the STOR request? :)
Your configuration seems ok , and even if it didn't you wouldn't get a
Command not implemented response! Can you check with Filezilla that the same
problem exists?




2010/5/24 Vishal1 Kumar <vi...@aricent.com>

>   Hi,
>
>
>
> I am implementing a NAT enabled router for one of my client software.
>
>
>
>
>
> I am having problem in FTP data connection establishment when a router is
> in between my ftp-client and ftp-server which is NAT enabled.
>
>
>
> The problem is, when I tried to make a data connection in active
> mode(port).
>
>
>
> I have implemented following in my router s/w for active mode
> data-connection:
>
> 1) I NAted the port command of FTP header at my router software(in addition
> to the IP NATing). So in response the ftp-server responded me [200 PORT
> command successful].
>
>      eg.
>
>          actual  client *Request command: PORT 192,168,255,241,14,42*
>
>          NATed client *Request command: PORT 10,10,10,10,14,42*
>
>          Response received from server: *200 PORT command successful* ->
> This response was forwarded to the client after required ip NATing.
>
>
>
> 2) Now when the ftp-client starts its data-connection with "STOR" command,
> my ftp-server responded back with [*502: Syntax error, command
> unrecognized*]
>
>     One other ftp server responded in the same scenario with error
> response: [*500: Command not implemen*ted]
>
>
>
> Now I checked all the check sum values in ip/tcp header; all seems fine. I
> am not able to track the exact problem even after performing the
> NAT required in FTP header to implement the active data mode connection.
>
>
>
>
>
> Can you find where I did wrong; Or can you please refer any place to look?
>
>
>
> Thanks in advance.
>
>
>
>
>
> Thanks and Regards,
>
> *Vishal Kumar***
>
> *Software Engineer** *
>
> *A R I C E N T*
>
>
>
> Electronic City, Plot 6
>
> Sector - 18, Gurgaon 122015
>
> Haryana, India
>
> Extn: 7737
>
> Mob no: +91 9717953693
>
>
>
> "DIAMOND is just another piece of COAL that did well under PRESSURE."
>
>
>
>
>
> ------------------------------
> "DISCLAIMER: This message is proprietary to Aricent and is intended solely
> for the use of the individual to whom it is addressed. It may contain
> privileged or confidential information and should not be circulated or used
> for any purpose other than for what it is intended. If you have received
> this message in error, please notify the originator immediately. If you are
> not the intended recipient, you are notified that you are strictly
> prohibited from using, copying, altering, or disclosing the contents of this
> message. Aricent accepts no responsibility for loss or damage arising from
> the use of the information transmitted by this email including damage from
> virus."
>