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Intermittent FTP rejects

Shailender_1
Advisor

Intermittent FTP rejects

For past one month we are facing intermittent FTP out to Tru64 Unix servers with following errors
%TCPIP-E-FTP_NETERR, I/O error on network device
-SYSTEM-F-REJECT, connect to network object rejected

We have couple of batch jobs schedule every 15 minutes to the Tru64 server. FTP works fine all the time but intermittently fails to connect to the server once in 3-4 days. Remote TRu64 (Receiving server doesn't record any log for the failed attempts.

OpenVMS server is Running VMS ver 7.3-1 with TCPIP 5.3 with ECO DEC AXPVMS TCPIP_ECO V5.3-184

We are unable to find the reason for failure. need help to get to the cause of the problem.
6 REPLIES
John Abbott_2
Esteemed Contributor

Re: Intermittent FTP rejects

Made any hardware or software changes recently ? patches ?

Is there a limit on the number of concurrent connects your Unix box can handle ?

Any firewalls or blocking rules that only allows certain interfaces from the VMS box to connect ?

Tried using TCPTRACE when you ftp ? (limit the runtime with /PACKETS=n and examine the output upon failure).

John.
Don't do what Donny Dont does
Martin Hughes
Regular Advisor

Re: Intermittent FTP rejects

Sounds like it is probably a network problem. I would modify your job to ping the remote server before and after the file transfer.
For the fashion of Minas Tirith was such that it was built on seven levels, each delved into a hill, and about each was set a wall, and in each wall was a gate. (J.R.R. Tolkien). Quote stolen from VAX/VMS IDSM 5.2
labadie_1
Honored Contributor

Re: Intermittent FTP rejects

Can you post the result of the following commands

$ ucx sh serv ftp/ful
$ mc authorize sh tcpip$ftp
$ search sys$sysdevice:<*ftp>tcpip$ftp_run.log;* "-E-","-F-"
Steven Schweda
Honored Contributor

Re: Intermittent FTP rejects

I thought that "SYSTEM-F-REJECT" was the
TCPIP equivalent of a UNIX "connection
refused" complaint, which happens when
there's no one (like an FTP server)
listening (or designated) on the remote
system. For example:

alp $ telnet /port = 666 localhost
%TELNET-I-TRYING, Trying ... 127.0.0.1
%TELNET-E-CONNFAIL, Failed to connect to remote host
-SYSTEM-F-REJECT, connect to network object rejected

In which case, I'd be looking for a problem
at the other end.
Shailender_1
Advisor

Re: Intermittent FTP rejects

The remote server is Live server, there are so many server sending FTP to this and Users are connected to this server round the clock. I don't see the possibility of Network outage, As no one other than FTP is failling that too once in 3-4 days. and my 4 different server sending ftp every 15 minutes to this server ony once in 3-4 days my request fails. What I understand there could be the following reasons.

1. FTP server is not running at the remote server, Which could not be the posibility as my next request is successfull.

2. Remote server's Max FTP concurrents session limit reached. (Does Tru64 Unix 5.x has controll over FTP concurrent session. Checked with Eng, he says they don't controll max session.)

If anyone know hos to check FTP session limit in Tru64 unix.

Steven Schweda
Honored Contributor

Re: Intermittent FTP rejects

> [...] FTP server is not running at the
> remote server, Which could not be the
> posibility [...]

inetd starts (or tries to start) an FTP
server (ftpd) when needed. You can't assume
that one is running when you need one, just
because one will run for someone else.

Perhaps some system-wide resource problem
could prevent inetd from spawning an FTP
server process from time to time, and that
might cause this symptom. (No bets.)

> [...] FTP session limit in Tru64 [...]

I don't know of one, but an inquiry in the
Tru64 forum might get you more.

Does anything appear in the Tru64 logs files?
There are ftpd options like "-d" and "-l"
which might be helpful. inetd has debug
options, too. Of course, it would be nice to
know if the problem is on the VMS side or the
Tru64 side before concentrating on one or the
other.