Net::SFTP is dropping connection when my program invokes ls, but only when the program is run by cron or 'at now'. Here's an example that demonstrates:

#!/opt/local/perl/bin/perl -w

use strict;
use Net::SFTP;

my $sftp = Net::SFTP->new("serverURL.com",
                       user => "myUser",
                       password => 'myPassword',
                       debug => 1);

my $targetDir = "/ftp/pub";

# connection dropped at this line when run from cron, but not from com
+mand line
my $lsHashRef = $sftp->ls($targetDir);

map
{
    my $filename = $_->{filename};
    print "$filename\n";
} sort {$a->{filename} cmp $b->{filename}} @$lsHashRef;

print "Done!\n";

[download]

The debug output from a successful command-line-invoked run:

lxdenvmap162: Reading configuration data /u/liveproc/.ssh/config
lxdenvmap162: Reading configuration data /etc/ssh_config
lxdenvmap162: Connecting to lxdenvmpc366.qintra.com, port 22.
lxdenvmap162: Remote version string: SSH-2.0-OpenSSH_4.3

lxdenvmap162: Remote protocol version 2.0, remote software version Ope
+nSSH_4.3
lxdenvmap162: Net::SSH::Perl Version 1.30, protocol version 2.0.
lxdenvmap162: No compat match: OpenSSH_4.3.
lxdenvmap162: Connection established.
lxdenvmap162: Sent key-exchange init (KEXINIT), wait response.
lxdenvmap162: Algorithms, c->s: 3des-cbc hmac-sha1 none
lxdenvmap162: Algorithms, s->c: 3des-cbc hmac-sha1 none
lxdenvmap162: Entering Diffie-Hellman Group 1 key exchange.
lxdenvmap162: Sent DH public key, waiting for reply.
lxdenvmap162: Received host key, type 'ssh-dss'.
lxdenvmap162: Host 'lxdenvmpc366.qintra.com' is known and matches the 
+host key.
lxdenvmap162: Computing shared secret key.
lxdenvmap162: Verifying server signature.
lxdenvmap162: Waiting for NEWKEYS message.
lxdenvmap162: Enabling incoming encryption/MAC/compression.
lxdenvmap162: Send NEWKEYS, enable outgoing encryption/MAC/compression
+.
lxdenvmap162: Sending request for user-authentication service.
lxdenvmap162: Service accepted: ssh-userauth.
lxdenvmap162: Trying empty user-authentication request.
lxdenvmap162: Authentication methods that can continue: publickey,pass
+word.
lxdenvmap162: Next method to try is publickey.
lxdenvmap162: Next method to try is password.
lxdenvmap162: Trying password authentication.
lxdenvmap162: Login completed, opening dummy shell channel.
lxdenvmap162: channel 0: new [client-session]
lxdenvmap162: Requesting channel_open for channel 0.
lxdenvmap162: channel 0: open confirm rwindow 0 rmax 32768
lxdenvmap162: channel 1: new [client-session]
lxdenvmap162: Requesting channel_open for channel 1.
lxdenvmap162: Sending subsystem: sftp
lxdenvmap162: Requesting service subsystem on channel 1.
lxdenvmap162: channel 1: open confirm rwindow 0 rmax 32768
lxdenvmap162: sftp: Sending SSH2_FXP_INIT
lxdenvmap162: sftp: Remote version: 3
lxdenvmap162: sftp: Sent message T:11 I:0
lxdenvmap162: sftp: Sent message T:12 I:1
lxdenvmap162: sftp: Received reply T:104 I:1
lxdenvmap162: sftp: Received 11 SSH2_FXP_NAME responses
lxdenvmap162: sftp: Sent message T:12 I:2
lxdenvmap162: sftp: Received reply T:101 I:2
lxdenvmap162: sftp: Received SSH2_FXP_STATUS 1
lxdenvmap162: sftp: Sent message T:4 I:3
.
..
XTRT.#CO.STRATA.RSKASAIF
XTRT.#CO.STRATA.RSKASAIF.bkp
XTRT.#EN.STRATA.RSKASAIF
XTRT.#ES.STRATA.RSKASAIF
XTRT.#NM.STRATA.RSKASAIF
XTRT.#OR.STRATA.RSKASAIF
XTRT.#UT.STRATA.RSKASAIF
XTRT.#WA.STRATA.RSKASAIF
processed
Done!

[download]

The debug output from a failed run using 'at now' to run it:

lxdenvmap162: Reading configuration data /u/liveproc/.ssh/config
lxdenvmap162: Reading configuration data /etc/ssh_config
lxdenvmap162: Connecting to lxdenvmpc366.qintra.com, port 22.
lxdenvmap162: Remote version string: SSH-2.0-OpenSSH_4.3

lxdenvmap162: Remote protocol version 2.0, remote software version Ope
+nSSH_4.3
lxdenvmap162: Net::SSH::Perl Version 1.30, protocol version 2.0.
lxdenvmap162: No compat match: OpenSSH_4.3.
lxdenvmap162: Connection established.
lxdenvmap162: Sent key-exchange init (KEXINIT), wait response.
lxdenvmap162: Algorithms, c->s: 3des-cbc hmac-sha1 none
lxdenvmap162: Algorithms, s->c: 3des-cbc hmac-sha1 none
lxdenvmap162: Entering Diffie-Hellman Group 1 key exchange.
lxdenvmap162: Sent DH public key, waiting for reply.
lxdenvmap162: Received host key, type 'ssh-dss'.
lxdenvmap162: Host 'lxdenvmpc366.qintra.com' is known and matches the 
+host key.
lxdenvmap162: Computing shared secret key.
lxdenvmap162: Verifying server signature.
lxdenvmap162: Waiting for NEWKEYS message.
lxdenvmap162: Enabling incoming encryption/MAC/compression.
lxdenvmap162: Send NEWKEYS, enable outgoing encryption/MAC/compression
+.
lxdenvmap162: Sending request for user-authentication service.
lxdenvmap162: Service accepted: ssh-userauth.
lxdenvmap162: Trying empty user-authentication request.
lxdenvmap162: Authentication methods that can continue: publickey,pass
+word.
lxdenvmap162: Next method to try is publickey.
lxdenvmap162: Next method to try is password.
lxdenvmap162: Trying password authentication.
lxdenvmap162: Login completed, opening dummy shell channel.
lxdenvmap162: channel 0: new [client-session]
lxdenvmap162: Requesting channel_open for channel 0.
lxdenvmap162: channel 0: open confirm rwindow 0 rmax 32768
lxdenvmap162: channel 1: new [client-session]
lxdenvmap162: Requesting channel_open for channel 1.
lxdenvmap162: Sending subsystem: sftp
lxdenvmap162: Requesting service subsystem on channel 1.
lxdenvmap162: channel 1: open confirm rwindow 0 rmax 32768
lxdenvmap162: sftp: Sending SSH2_FXP_INIT
lxdenvmap162: sftp: Remote version: 3
lxdenvmap162: sftp: Sent message T:11 I:0
lxdenvmap162: channel 1: rcvd eof
lxdenvmap162: channel 1: output open -> drain
lxdenvmap162: channel 1: obuf empty
lxdenvmap162: channel 1: output drain -> closed
lxdenvmap162: channel 1: close_write
lxdenvmap162: channel 1: rcvd close
lxdenvmap162: channel 1: input open -> closed
lxdenvmap162: channel 1: close_read
lxdenvmap162: channel 1: send close
lxdenvmap162: channel 1: full closed
Connection closed at ./problem.pl line 13

[download]

I know this isn't likely to be Perl-specific, but please, oh mighty monks, do any of you have a guess about why this is happening?

In reply to Net::SFTP disconnect by gregor-e

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