After hooking up a network sniffer to the terminal server and observing the behavior, it has come to light that the terminal server is closing the TCP/IP connection with LPRng after 8 keepalive packets.
This has gone unnoticed because our existing printer software simply continues to reconnect where it left off. LPRng decides the job is done when the connection is closed (not terminated). Is there a way to work around this behavior? I'm trying out using netcat as a printer filter, with little success so far. Input is appreciated. Russell On Wed, Apr 07, 2004 at 09:23:21PM -0500, Russell Adams wrote: > Testing our new print server on Redhat ES 2.1 and using LPRng-3.8.26, > I had a disturbing error during my testing. > > As part of documenting the behavior of LPRng when a partial failure > occurs on the printer side, we sent a 1 Megabyte print job to a > Okidata line printer hooked up to an old DEC terminal server. 75% of > my printers use this configuration. > > After about 2k of print had printed, we stopped the printer from > printing via taking it offline on the operator panel. The printer was > not turned off or disconnected. In this state with our existing > system, when we turned the printer back online 30 minutes later, it > should have resumed where it left off. The terminal servers asks the > host transmitting the data to wait until the serial line flow control > turns off again. > > It did resume printing, but ceased as soon as it finished with the 16k > buffer contents. The remainder of the job did not come through. > > The queue status on the LPRng server reported that the print had > complete successfully. > > It seems to me that the raw socket printing failed to stop > transmitting while the terminal server could not accept additional > input, losing the rest of the job. > > I'm going to start troubleshooting this in earnest in the morning, but > I'm looking for suggestions as to where to start. I'll likely put our > sniffer on it. > > Here is my printcap for the printer: > > .common > :sd=/var/spool/lpd/%P > :sh > :if=/usr/local/libexec/filters/lpf > > H2FC | h2fc > :tc=.common > :lp=ts1-ELRIO.ksnet.com%2028 > :cm="ELRIO COMPUTER ROOM" > > I've considered perhaps we should use an alternate program to print to > slow devices requiring buffering (ie: netcat). I believe we used to > use a telnet filter, which may be from > > http://h18003.www1.hp.com/support/digital_networks_archive/servers/tips/telnet.c > > , however I did not previously have the source code. > > Any suggestions are appreciated. > > Russell > > ----------------------------------------------------------------------------- > YOU MUST BE A LIST MEMBER IN ORDER TO POST TO THE LPRNG MAILING LIST > The address you post from MUST be your subscription address > > If you need help, send email to [EMAIL PROTECTED] (or lprng-requests > or lprng-digest-requests) with the word 'help' in the body. For the impatient, > to subscribe to a list with name LIST, send mail to [EMAIL PROTECTED] > with: | example: > subscribe LIST <mailaddr> | subscribe lprng-digest [EMAIL PROTECTED] > unsubscribe LIST <mailaddr> | unsubscribe lprng [EMAIL PROTECTED] > > If you have major problems, send email to [EMAIL PROTECTED] with the word > LPRNGLIST in the SUBJECT line. > ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- YOU MUST BE A LIST MEMBER IN ORDER TO POST TO THE LPRNG MAILING LIST The address you post from MUST be your subscription address If you need help, send email to [EMAIL PROTECTED] (or lprng-requests or lprng-digest-requests) with the word 'help' in the body. For the impatient, to subscribe to a list with name LIST, send mail to [EMAIL PROTECTED] with: | example: subscribe LIST <mailaddr> | subscribe lprng-digest [EMAIL PROTECTED] unsubscribe LIST <mailaddr> | unsubscribe lprng [EMAIL PROTECTED] If you have major problems, send email to [EMAIL PROTECTED] with the word LPRNGLIST in the SUBJECT line. -----------------------------------------------------------------------------
