Workshop

I Can’t Spool, Take Two
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I was in a shop that bought a new UNIX host, moved some print queues over, and noticed during
testing that certain print jobs would just sit there for long periods of time before printing. We noticed
that this only happened with wide area–connected printers, as well as printers that were connected to
dedicated print servers.
We further noticed that only one printer at a time was printing on any given standalone print server.
Our host vendor claimed that it had to be our network, whereas our print server vendor said it had to be
the host.
After sending print jobs to multiple queues from the host to one of our standalone print servers, I went
to the host and typed the following:
netstat -an | grep 515
I only saw one socket being opened to the print server. That was enough evidence for me—apparently,
the print services on this (proprietary) version of UNIX didn’t support more than one printer on a given
network host, and it was only sending one job at a time. This was why the wide area stuff was acting
funny, too—there were more than one printer on the other side of the WAN link, and instead of
sending multiple print jobs, one big print job could block all the other, smaller print jobs. Network
traces bore this out.
The vendor claimed that this aberrant behavior was “as designed,” and declined to fix it. So we went
and bought something that worked right.
Content Checker
For certain services, such as HTTP, you can actually check content. For instance, Listing 18.1 shows a
troubleshooting session with a Web server.
Listing 18.1 A Troubleshooting Session with a Web Server
mori A ~$ telnet 167.195.160.6 80
Trying 167.195.160.6…