JohnAllen.us

Anyone who has ever worked with networks at one point or another always ends up running a telnet or ping command over and over again to generate traffic and check if one computer can talk to another. After running that command a couple dozen times, one starts to think that maybe it would be better to write a program to do this instead.

One of my customers has a number of RedHat servers that I’m not allowed to install any programing language like Ruby or Perl on that I would normally use to write such a program…however, they have a complete Python installation for some reason. Not to argue with fate, I wrote the following script to run my tests with:

#
# nettest.py
#
import sys
import socket
import time

host = sys.argv[1]
port = int(sys.argv[2])
# type => ["tcp" or "udp"]
type = sys.argv[3]
test = ""
if len(sys.argv) > 4 :
 test = sys.argv[4]

while 1 :
  if type == "udp":
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
  else:
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
  s.settimeout(5)
  try:
    if type == "udp":
      s.sendto("--TEST LINE--", (host, port))
      recv, svr = s.recvfrom(255)
      s.shutdown(2)
      print "Success connecting to " + host + " on UDP port: " + str(port)
    else:
      s.connect((host, port))
      s.shutdown(2)
      print "Success connecting to " + host + " on TCP port: " + str(port)
  except Exception, e:
    try:
      errno, errtxt = e
    except ValueError:
      print "Cannot connect to " + host + " on port: " + str(port)
    else:
      if errno == 107:
        print "Success connecting to " + host + " on UDP port: " + str(port)
      else:
        print "Cannot connect to " + host + " on port: " + str(port)
        print e
  if test != "C" :
    sys.exit(0)

  s.close
  time.sleep(1)

This is run like so: Continue reading »