FTPWebRequest Fails on Some FTP Sites

21 Feb 2006 6:43 PM

Frank Walker

I posted this problem a week ago, and received no response, so here it is
again...

While using FTPWebRequest, I have found at least one FTP site where this
function fails.
The URI I am using is ftp://nssdca.gsfc.nasa.gov/md_doc/app_a.doc

This NASA ftp site is available through anonymous log in, and other FTP
clients, including Internet Explorer using FTP protocols, download the file
just fine.

As the capture below shows, when FTPWebRequest sends PWD, it receives
ANON_DIR:[000000] from the ftp site.

Then when FTPWebRequest sends CWD ANON_DIR:[000000]/md_doc/ it receives an
error of 550, then it gives up and closes the connection.

Any advice on this would be helpful.

Thanks,

Frank Walker

No.     Time        Source                Destination       Protocol Info
    656 127.450368 130.14.60.135         128.183.241.14        TCP
2888 > ftp [SYN] Seq=0 Ack=0 Win=65535 Len=0 MSS=1460

    659 127.454361 130.14.60.135         128.183.241.14        TCP
2888 > ftp [ACK] Seq=1 Ack=1 Win=65535 Len=0

    660 127.459681 128.183.241.14        130.14.60.135         FTP
Response: 220 ndadsb.gsfc.nasa.gov MultiNet FTP Server Process V4.2(16) at
Tue 14-Feb-2006 9:10AM-EST

    661 127.459876 130.14.60.135         128.183.241.14        FTP
Request: USER anonymous

    662 127.527600 128.183.241.14        130.14.60.135         FTP
Response: 331 anonymous user ok. Send real ident as password.

    663 127.527751 130.14.60.135         128.183.241.14        FTP
Request: PASS MYUSER@

    670 128.539245 128.183.241.14        130.14.60.135         FTP
Response: 230-Guest User MYUSER@ logged into ANON_DIR:[000000] at Tue
14-Feb-2006 9:10AM-EST, job 4280ad34.

    674 128.690469 128.183.241.14        130.14.60.135         FTP
Response: 230 Directory and access restrictions apply

    675 128.690726 130.14.60.135         128.183.241.14        FTP
Request: PWD

    676 128.695622 128.183.241.14        130.14.60.135         FTP
Response: 257 "ANON_DIR:[000000]" is current directory.

    677 128.695731 130.14.60.135         128.183.241.14        FTP
Request: CWD ANON_DIR:[000000]/md_doc/

    678 128.702017 128.183.241.14        130.14.60.135         FTP
Response: 550 %RMS-F-SYN, file specification syntax error:
ANON_DIR:[000000]/md_doc/

    679 128.705557 130.14.60.135         128.183.241.14        TCP
2888 > ftp [FIN, ACK] Seq=67 Ack=414 Win=65122 Len=0

21 Feb 2006 8:12 PM

AlexL [Xceed]

I have no helpful advice for using the free FTPWebRequest class from
Microsoft, but I can sure tell you that if you use a 3rd party tool
(such as ours) that this works without any problems.

The C# code to fetch "app_a.doc" from that FTP server is:

      Xceed.Ftp.FtpClient client = new Xceed.Ftp.FtpClient();

      client.Connect("nssdca.gsfc.nasa.gov");
      client.Login(); // Anonymous
      client.ChangeCurrentFolder("md_doc");

      client.ReceiveFile("app_a.doc", @"d:\app_a.doc");

Voila!

Our product, Xceed FTP for .NET product is:

http://www.xceedsoft.com/products/ftpnet

Hope this helps.

On Tue, 21 Feb 2006 13:43:16 -0500, "Frank Walker"
<wal***@nlm.nih.gov> wrote:

Show quote

>I posted this problem a week ago, and received no response, so here it is
>again...
>
>While using FTPWebRequest, I have found at least one FTP site where this
>function fails.
>The URI I am using is ftp://nssdca.gsfc.nasa.gov/md_doc/app_a.doc
>
>This NASA ftp site is available through anonymous log in, and other FTP
>clients, including Internet Explorer using FTP protocols, download the file
>just fine.
>
>As the capture below shows, when FTPWebRequest sends PWD, it receives
>ANON_DIR:[000000] from the ftp site.
>
>Then when FTPWebRequest sends CWD ANON_DIR:[000000]/md_doc/ it receives an
>error of 550, then it gives up and closes the connection.
>
>Any advice on this would be helpful.
>
>Thanks,
>
>Frank Walker
>
>
>
>No.     Time        Source                Destination       Protocol Info
>    656 127.450368 130.14.60.135         128.183.241.14        TCP
>2888 > ftp [SYN] Seq=0 Ack=0 Win=65535 Len=0 MSS=1460
>
>    659 127.454361 130.14.60.135         128.183.241.14        TCP
>2888 > ftp [ACK] Seq=1 Ack=1 Win=65535 Len=0
>
>    660 127.459681 128.183.241.14        130.14.60.135         FTP
>Response: 220 ndadsb.gsfc.nasa.gov MultiNet FTP Server Process V4.2(16) at
>Tue 14-Feb-2006 9:10AM-EST
>
>    661 127.459876 130.14.60.135         128.183.241.14        FTP
>Request: USER anonymous
>
>    662 127.527600 128.183.241.14        130.14.60.135         FTP
>Response: 331 anonymous user ok. Send real ident as password.
>
>    663 127.527751 130.14.60.135         128.183.241.14        FTP
>Request: PASS MYUSER@
>
>    670 128.539245 128.183.241.14        130.14.60.135         FTP
>Response: 230-Guest User MYUSER@ logged into ANON_DIR:[000000] at Tue
>14-Feb-2006 9:10AM-EST, job 4280ad34.
>
>    674 128.690469 128.183.241.14        130.14.60.135         FTP
>Response: 230 Directory and access restrictions apply
>
>    675 128.690726 130.14.60.135         128.183.241.14        FTP
>Request: PWD
>
>    676 128.695622 128.183.241.14        130.14.60.135         FTP
>Response: 257 "ANON_DIR:[000000]" is current directory.
>
>    677 128.695731 130.14.60.135         128.183.241.14        FTP
>Request: CWD ANON_DIR:[000000]/md_doc/
>
>    678 128.702017 128.183.241.14        130.14.60.135         FTP
>Response: 550 %RMS-F-SYN, file specification syntax error:
>ANON_DIR:[000000]/md_doc/
>
>    679 128.705557 130.14.60.135         128.183.241.14        TCP
>2888 > ftp [FIN, ACK] Seq=67 Ack=414 Win=65122 Len=0
>
>

--
Alex Leblanc
Xceed Software Inc.
http://www.xceedsoft.com

Check out our advanced .NET zip file and compression library

Email: xLebla***@xceedsoft.com (remove the first 'x')

22 Feb 2006 2:35 PM

Kevin Spencer

Hi Frank,

The URI is a URI to an anonymously-available document (I just clikced on the
URI to get it). Why would you then send a CWD command?

--
HTH,

Kevin Spencer
Microsoft MVP
..Net Developer
To a tea you esteem
a hurting back as a wallet.

Show quote

"Frank Walker" <wal***@nlm.nih.gov> wrote in message
news:ucWRvaxNGHA.3556@TK2MSFTNGP10.phx.gbl...
>I posted this problem a week ago, and received no response, so here it is
>again...
>
> While using FTPWebRequest, I have found at least one FTP site where this
> function fails.
> The URI I am using is ftp://nssdca.gsfc.nasa.gov/md_doc/app_a.doc
>
> This NASA ftp site is available through anonymous log in, and other FTP
> clients, including Internet Explorer using FTP protocols, download the
> file just fine.
>
> As the capture below shows, when FTPWebRequest sends PWD, it receives
> ANON_DIR:[000000] from the ftp site.
>
> Then when FTPWebRequest sends CWD ANON_DIR:[000000]/md_doc/ it receives an
> error of 550, then it gives up and closes the connection.
>
> Any advice on this would be helpful.
>
> Thanks,
>
> Frank Walker
>
>
>
> No.     Time        Source                Destination       Protocol Info
>    656 127.450368 130.14.60.135         128.183.241.14        TCP
> 2888 > ftp [SYN] Seq=0 Ack=0 Win=65535 Len=0 MSS=1460
>
>    659 127.454361 130.14.60.135         128.183.241.14        TCP
> 2888 > ftp [ACK] Seq=1 Ack=1 Win=65535 Len=0
>
>    660 127.459681 128.183.241.14        130.14.60.135         FTP
> Response: 220 ndadsb.gsfc.nasa.gov MultiNet FTP Server Process V4.2(16) at
> Tue 14-Feb-2006 9:10AM-EST
>
>    661 127.459876 130.14.60.135         128.183.241.14        FTP
> Request: USER anonymous
>
>    662 127.527600 128.183.241.14        130.14.60.135         FTP
> Response: 331 anonymous user ok. Send real ident as password.
>
>    663 127.527751 130.14.60.135         128.183.241.14        FTP
> Request: PASS MYUSER@
>
>    670 128.539245 128.183.241.14        130.14.60.135         FTP
> Response: 230-Guest User MYUSER@ logged into ANON_DIR:[000000] at Tue
> 14-Feb-2006 9:10AM-EST, job 4280ad34.
>
>    674 128.690469 128.183.241.14        130.14.60.135         FTP
> Response: 230 Directory and access restrictions apply
>
>    675 128.690726 130.14.60.135         128.183.241.14        FTP
> Request: PWD
>
>    676 128.695622 128.183.241.14        130.14.60.135         FTP
> Response: 257 "ANON_DIR:[000000]" is current directory.
>
>    677 128.695731 130.14.60.135         128.183.241.14        FTP
> Request: CWD ANON_DIR:[000000]/md_doc/
>
>    678 128.702017 128.183.241.14        130.14.60.135         FTP
> Response: 550 %RMS-F-SYN, file specification syntax error:
> ANON_DIR:[000000]/md_doc/
>
>    679 128.705557 130.14.60.135         128.183.241.14        TCP
> 2888 > ftp [FIN, ACK] Seq=67 Ack=414 Win=65122 Len=0
>
>
>

23 Feb 2006 7:34 PM

Frank Walker

Kevin,

That's the question I have: why is FTPWebRequest doing this?
I think the person who designed this function may not have tested
it on many FTP sites. Internet Explorer certainly doesn't have this problem.

Once logged into the FTP site, IE issues a RETR /md_doc/app_a.doc ,
and avoids the problem with CWD.

Frank Walker

Show quote

"Kevin Spencer" <kevin@DIESPAMMERSDIEtakempis.com> wrote in message
news:%23bit007NGHA.456@TK2MSFTNGP15.phx.gbl...
> Hi Frank,
>
> The URI is a URI to an anonymously-available document (I just clikced on
> the URI to get it). Why would you then send a CWD command?
>
> --
> HTH,
>
> Kevin Spencer
> Microsoft MVP
> .Net Developer
> To a tea you esteem
> a hurting back as a wallet.
>
>
> "Frank Walker" <wal***@nlm.nih.gov> wrote in message
> news:ucWRvaxNGHA.3556@TK2MSFTNGP10.phx.gbl...
>>I posted this problem a week ago, and received no response, so here it is
>>again...
>>
>> While using FTPWebRequest, I have found at least one FTP site where this
>> function fails.
>> The URI I am using is ftp://nssdca.gsfc.nasa.gov/md_doc/app_a.doc
>>
>> This NASA ftp site is available through anonymous log in, and other FTP
>> clients, including Internet Explorer using FTP protocols, download the
>> file just fine.
>>
>> As the capture below shows, when FTPWebRequest sends PWD, it receives
>> ANON_DIR:[000000] from the ftp site.
>>
>> Then when FTPWebRequest sends CWD ANON_DIR:[000000]/md_doc/ it receives
>> an
>> error of 550, then it gives up and closes the connection.
>>
>> Any advice on this would be helpful.
>>
>> Thanks,
>>
>> Frank Walker
>>
>>
>>
>> No.     Time        Source                Destination       Protocol Info
>>    656 127.450368 130.14.60.135         128.183.241.14        TCP
>> 2888 > ftp [SYN] Seq=0 Ack=0 Win=65535 Len=0 MSS=1460
>>
>>    659 127.454361 130.14.60.135         128.183.241.14        TCP
>> 2888 > ftp [ACK] Seq=1 Ack=1 Win=65535 Len=0
>>
>>    660 127.459681 128.183.241.14        130.14.60.135         FTP
>> Response: 220 ndadsb.gsfc.nasa.gov MultiNet FTP Server Process V4.2(16)
>> at
>> Tue 14-Feb-2006 9:10AM-EST
>>
>>    661 127.459876 130.14.60.135         128.183.241.14        FTP
>> Request: USER anonymous
>>
>>    662 127.527600 128.183.241.14        130.14.60.135         FTP
>> Response: 331 anonymous user ok. Send real ident as password.
>>
>>    663 127.527751 130.14.60.135         128.183.241.14        FTP
>> Request: PASS MYUSER@
>>
>>    670 128.539245 128.183.241.14        130.14.60.135         FTP
>> Response: 230-Guest User MYUSER@ logged into ANON_DIR:[000000] at Tue
>> 14-Feb-2006 9:10AM-EST, job 4280ad34.
>>
>>    674 128.690469 128.183.241.14        130.14.60.135         FTP
>> Response: 230 Directory and access restrictions apply
>>
>>    675 128.690726 130.14.60.135         128.183.241.14        FTP
>> Request: PWD
>>
>>    676 128.695622 128.183.241.14        130.14.60.135         FTP
>> Response: 257 "ANON_DIR:[000000]" is current directory.
>>
>>    677 128.695731 130.14.60.135         128.183.241.14        FTP
>> Request: CWD ANON_DIR:[000000]/md_doc/
>>
>>    678 128.702017 128.183.241.14        130.14.60.135         FTP
>> Response: 550 %RMS-F-SYN, file specification syntax error:
>> ANON_DIR:[000000]/md_doc/
>>
>>    679 128.705557 130.14.60.135         128.183.241.14        TCP
>> 2888 > ftp [FIN, ACK] Seq=67 Ack=414 Win=65122 Len=0
>>
>>
>>
>
>