HP-UX HB v13.00 Ch-09 - Networking Basics

HP-UX Handbook – Rev 13.00 Page 23 (of 27)
Chapter 09 Network Basics
October 29, 2013
XPORT/Pages/NDD%20parameters/nddparams.aspx, (HP-Internal).
Trace tools
If there are any problems or unexpected effects in the network it is often really helpful to check
the network communication directly. There are some easy to use programs available for this
purpose. This is a short introduction to the most common tools:
nettl
The nettl command is a tool to monitor problems within the network and to trace the complete
network communication. It is included in each HP-UX installation; it is the “ready to use” tool
for administrators to do first checks. Unfortunately, there are some limitations. First, there are
different versions available. Newer versions have more options to adapt it to the needs of current
hardware generations. Please check the man page. Second, it is sometimes too slow to capture all
traffic on 1Gbit or faster networks. Nevertheless, here is a short introduction to this tool. It is
usually started by the init process with the script:
/sbin/rc2.d/S200nettl
When started by this default procedure, it logs problematic events in network only. You can
configure it, if required, in /etc/rc.config.d/nettl.
The output of the command:
# nettl –status
shows if it is running, location and size of the log files, and which subsystems are observed for
“ERROR” and “DISASTER” events. The line “No Subsystems Active” in the output means that
currently only problematic events are observed, and the tracing part of nettl is not active.
To capture network packages, use the following steps:
Check, if nettl is running:
# nettl –status
if not yet started, start it with:
# nettl –start
Start tracing:
# nettl –tn pduin pduout –e ns_ls_ip –tm 99999 –f /tmp/my-trc
Run the command/process which should be observed and stop tracing directly afterwards, with
the command:
# nettl –tf –e all
The trace tool writes a binary output in one or two files /tmp/my-trc.TRC0*. It uses a circular
output file method, which means, as soon as one file fills up, another file is used. As soon as the
second file fills up, the first file gets overwritten. The size of both output files together is limited