As Kyle has discovered, the "mx" parameter has been rendered worse than useless by situations where the LPR client is a spooler. Or perhaps to be more specific, a Windows spooler.

It would be helpful if the server behavior were to accept a print job until it exceeds the size limit, then remove the job file (or truncate it to 0 bytes) and continue to read the incoming job, sending it to the bit bucket. The response to the client should be "Yup, got it, everything's just fine, have a nice day".

The current behavior, as I understand it, is to terminate the job transfer session with an error. The Windows spooler will then retry the transfer. This creates a denial of service risk unless you have infinite amounts of network bandwidth, CPU power, and disk space.

It would be interesting to know if this is only a problem with Windows LPR clients, or whether it also happens with, say, an LPRng spooler sending jobs to another LPRng spooler. That is, is Microsoft's LPR implementation behaving badly. A totally academic excercise, but interesting nonetheless.

-Rick

Kyle Billups wrote:
Hello,

We may have fixed our problem.  Our max size per job was 10 MB.  So when a
PC sent a print job that was over 10 MB, it flooded the queue with 999 hf
files (each with a size of 0) every 4 sec.  However from a mac, it sent
one hf file with a size of 0.  So we made the following changes to the
printcap.local:

1.  Changed mx=10240 to mx#0
2.  Changed ifhp=model=hp8150 to ifhp=model=hp8100.

Currently, we are trying to fix the 79.00FE errors that we are receiving
on our printers.  We upgraded the printers' firmware; however, we
are still getting that error.  We are going to increase the "TCP/IP idle
timeout" mentioned in a previous post.

Advanced Thanks,
Kyle


On Wed, 27 Aug 2003, Kyle Billups wrote:



Hello,

One of our computers was sending repetitive lpr requests until our queue
become full.  I took a look in the /var/spool/lpd/eng-bill directory and
noticed that we had 999 hf files (001 to 999).  The problem is that only
one hf file had corresponding cf/df files.  I checked the queue using
'lpq' and noticed that the jobs (without the cf/df files) were sent every
4 seconds with a size of 0.  Here is a segment of the lpq output:

Printer: [EMAIL PROTECTED] (dest [EMAIL PROTECTED]) (holdall)
Queue: no printable jobs in queue
Holding: 1 held jobs in queue
Server: no server active
Status: job '[EMAIL PROTECTED]' removed at 14:46:28.414
Filter_status: done at 14:46:27.562
Rank   Owner/ID         Class Job    Files             Size    Time
hold   [EMAIL PROTECTED]            A   3 https://webmail.uiu  100616 10:25:41
hold   [EMAIL PROTECTED]   A   1 Microsoft PowerPoint   0    11:19:29
hold   [EMAIL PROTECTED]   A   5 Microsoft PowerPoint   0    11:19:30
hold   [EMAIL PROTECTED]   A   6 Microsoft PowerPoint   0    11:19:34
hold   [EMAIL PROTECTED]   A   7 Microsoft PowerPoint   0    11:19:38
hold   [EMAIL PROTECTED]   A   8 Microsoft PowerPoint   0    11:19:42
hold   [EMAIL PROTECTED]   A   9 Microsoft PowerPoint   0    11:19:46
hold   [EMAIL PROTECTED]   A  10 Microsoft PowerPoint   0    11:19:50
...

We temporarily fixed the problem by turning off eng-pc15, and removing its
print jobs from the print queue.  This computer was printing correctly
before this incident, and is printing fine now.  Does anyone know why this
occurred?  If so, is there a permanent solution?

Here is our printcap.local file:

.common:\
       :sd=/var/spool/lpd/%P:\
       :mx=10240:\
       :bk:\
       :sh:\
       :filter=/usr/lib/lpfilters/ifhp:

.filter1:\
       :force_ipaddr_hostname:\
:control_filter=/home/www/htdocs/arete/webPrint/filter/printFilter2.pl:\
:incoming_control_filter=/home/www/htdocs/arete/webPrint/filter/printFilter1.pl:

eng-bill:\
       :tc=.common,.filter1:\
       :ifhp=model=hp8150:\
       :[EMAIL PROTECTED]:


Advanced Thanks, Kyle

-------------------------------------------------------------------------------
Kyle Billups
Programmer Consultant
University of Illinois
CITES Instructional Computing Sites (ICS)
email:  [EMAIL PROTECTED]



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Kyle Billups
Programmer Consultant
University of Illinois
CITES Instructional Computing Sites (ICS)
email:  [EMAIL PROTECTED]


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-- |Rick Cochran phone: 607-255-7618| |Cornell CIT - Systems & Operations - Net-Print FAX: 607-255-8521| |730 Rhodes Hall, Ithaca, N.Y. 14853 email: [EMAIL PROTECTED]|


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