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Re: %TCPIP-E-FTP_SEND, cannot send on socket (for large files)

 
Arno van Rennes
Advisor

%TCPIP-E-FTP_SEND, cannot send on socket (for large files)

After installing OpenVMS 7.3-2 and TCPIP V5.4 - ECO 5, putting large files via FTP from an Alpha to a IBM system does not work anymore. The remote (IBM) system seems to see the session as idle and disconnects it after 5 minutes.

The file to put is about 10,5 Mb and gets the next error:

$ ftp IBMSYSTEM
220-GIDSFTP1 IBM FTP CS V1R4 at BG08, 18:22:47 on 2005-10-24.
220 Connection will close if idle for more than 5 minutes.
Connected to IBMSYSTEM.
Name (IBMSYSTEM:cnrennes): username
331 Send password please.
Password:
230 USERNAME is logged on. Working directory is "USERNAME.".
FTP> put INTERTMP:CL_250.NIEUW_AP RI.DATA.XXX.FTP
200 Port request OK.
125 Storing data set RI.DATA.XXX.FTP
()
STVMS1::CNRENNES_1 18:22:24 TCPIP$FTP CPU=00:00:44.73 PF=37668 IO=189408 MEM=327
PUT (ASCII) 61464 bytes 00:00:02.23 elapsed (26.83 KB/S)
Local: DISK99:[SINX_INTER_DAT.TMP]CL_250_24_B_M_IC_RUN_XCAS.NIEUW_AP;1
Remote: RI.DATA.ST25024X.FTP

%TCPIP-E-FTP_SEND, cannot send on socket
-SYSTEM-F-LINKDISCON, network partner disconnected logical link
525 No data is available on the data connection
FTP> ()
STVMS1::CNRENNES_1 18:27:24 TCPIP$FTP CPU=00:00:44.73 PF=37711 IO=189421 MEM=327
FTP> Exit


Of course before the upgrade (with OpenVMS 7.1-2 and UCX V4.2 - ECO 5) there was no problem putting large files to the IBM system.
And on the site of the IBM system there were no changes.

Putting a small file to the IBM system is still working all right.

Who can help me with this!

Regards,
Arno van Rennes
16 REPLIES 16
Karl Rohwedder
Honored Contributor

Re: %TCPIP-E-FTP_SEND, cannot send on socket (for large files)

Arno,

was anything else changed? The speed of 26KB/sec sounds quite slow to me (or is it, because it's an IBM :-)?

regards Kalle
Arno van Rennes
Advisor

Re: %TCPIP-E-FTP_SEND, cannot send on socket (for large files)

Hi Kalle,

No, as far as I know, nothing else has been changed.
Sending verry large files (>200000 blocks) between our own VMS systems runs at 5917KB/sec.
So that must be the IBM-system :-).
(or our setting?)

Regards,
Arno

Andy Bustamante
Honored Contributor

Re: %TCPIP-E-FTP_SEND, cannot send on socket (for large files)


Is there a firewall between the IBM and VMS systems? See the TCPIP release notes section 3.9

http://h71000.www7.hp.com/doc/732FINAL/TCP_RN/tcp_rnpro_002.html#ftp_problems

Previous versions of TCPIP would accpet ftp-data on something other than port 20. This showed a few firewall issues. You can restore the old behavior or check the firewall configuration.

Andy
If you don't have time to do it right, when will you have time to do it over? Reach me at first_name + "." + last_name at sysmanager net
Michael Yu_3
Valued Contributor

Re: %TCPIP-E-FTP_SEND, cannot send on socket (for large files)

Hi Arno,

The problem was probably caused by the firewall which kills TCP sessions after they have been idle for 5 minutes.

FTP sent data on the data channel but the control channel will be idle. I think the firewall has terminated the control channel and hence the data channel is also disconnected.

UCX V4.2 worked because the keepalive timer was set to 75 seconds. TCP/IP V5.4 is different. By default, keepalive is disabled (tcp_keepalive_default = 0) and even if it is enabled, the default keepalive timer is 7200 seconds (tcp_keepidle = 14400).

If my guess is correct, this problem can be solved by enabling keepalive and by setting the keepalive timer shorter than 5 minutes (300 seconds).

So before you FTP to the IBM, try the following.

$ @sys$manager:tcppip$define_commands
$ sysconfig -r inet tcp_keepalive_default=1
$ sysconfig -r inet tcp_keepidle=500

The above will enable keepalive and set the keepalive timer to 500 half-seconds, i.e. 250 seconds.

Hope the above helps.

Remember the changes above will affect all new TCP connections, you may choose to restore the original settings after the FTP. Also these settings are volatile, they will not survive reboots unless you make them permanent using sysconfigdb.

Thanks and regards.

Michael
Arno van Rennes
Advisor

Re: %TCPIP-E-FTP_SEND, cannot send on socket (for large files)

Hi Michael,

Unfortunately, setting tcp_keepalive_default=1 and tcp_keepidle=500 makes no difference.

After exactly 5 minutes:
%TCPIP-E-FTP_SEND, cannot send on socket
-SYSTEM-F-LINKDISCON, network partner disconnected logical link
525 No data is available on the data connection

Thanks,
Arno
Arno van Rennes
Advisor

Re: %TCPIP-E-FTP_SEND, cannot send on socket (for large files)

Hi Andy,

I read the release notes but I don't see a direct relation whit this issue.
The way I read it there will be no connection at all, and in this case small files can be put to the IBM system, only the connection with large files is terminated after 5 minutes.
Please correct me if I'm wrong.

Thanks,
Arno
Wim Van den Wyngaert
Honored Contributor

Re: %TCPIP-E-FTP_SEND, cannot send on socket (for large files)

Arno,

I would say that the FTP server on the IBM aborted and VMS stayed alive and the connection was stopped by keepalive. Check on the IBM. How much of the file arrived ?

If there is a firewall, I once had a problem with it. Read the enclosure. It talks about a trace I sent them of an analogue problem.

Wim

Wim
Arno van Rennes
Advisor

Re: %TCPIP-E-FTP_SEND, cannot send on socket (for large files)

Hi Wim,

I cannot check on the IBM system, this is at a bank.
I did talk to then and they don't see anything faulty when I send the large file.

I have tested it with the settings in your attachment:
ipport_userreserved_min = 1024
ipport_userreserved = 5000
tcp_keepalive_default = 1
tcp_keepidle = 500

and

ipport_userreserved_min = 1024
ipport_userreserved = 5000
tcp_keepalive_default = 0
tcp_keepidle = 14400

Unfortunately this also did not work.

I've also set the passif mode from "Passive is AUTO (IPv4: OFF, IPv6: ON)" to "Passive is OFF" but also no results.

Thanks,
Arno
Wim Van den Wyngaert
Honored Contributor

Re: %TCPIP-E-FTP_SEND, cannot send on socket (for large files)

Arno,

I also work in a bank and know how you feel.

Did the IBM receive part of the file ?

Wim
Wim