How to test general connectivity using Ping - Telnet - Netstat on Windows

Products

• Data Loss Prevention Endpoint Prevent

Issue/Introduction

You have either Detection servers, Oracle, or Endpoint agents that lose connectivity every now and then, or fail to check in.

Resolution

The two main areas to check are: Port Connectivity, and Ping/connection timeouts or dropped packets.

Port Connectivity: Is the port open?
telnet <server name> port#
e.g.
Telnet <server name> 8100

If the port is open you should be taken to a blank screen, otherwise you may receive a "Connection Refused" error.
NOTE: Missing Telnet? Check for additional features via Add/Remove Programs; Telnet is typically not 'installed' on Windows 10 and Windows 2016

Is the Port Listening for connections?
You can also use the netstat command to see if a port is 'Listening' or established:
Example of seeing if a Detection server is listening on port 8100 for a connection request from Enforce=
On the Detection server via a Command window:
C:\>netstat -aon | find "8100"
TCP 0.0.0.0:8100           0.0.0.0:0                    LISTENING      3740
TCP 192.0.2.1:8100  192.0.2.1:63843    ESTABLISHED 3740

If Enforce is sees the detection server you should see an ESTABLISHED connection.
Where 192.0.2.1 is a Detection server waiting for a request on Port 8100, and 192.0.2.1 is Enforce Established connectivity on a random port, in this example, Port 63843

Can you Ping the remote system, and does the response drop packets?
Ping request response time:
Basic command - ping <server name>
e.g.

C:\>ping <server name>

Pinging <server name> [192.0.2.1] with 32 bytes of data:
Reply from 192.0.2.1: bytes=32 time<1ms TTL=128
Reply from 192.0.2.1: bytes=32 time<1ms TTL=128
Reply from 192.0.2.1: bytes=32 time<1ms TTL=128
Reply from 192.0.2.1: bytes=32 time<1ms TTL=128

Ping statistics for 192.0.2.1:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 0ms, Average = 0ms

 

Advanced command - ping <number of packets> <buffer size/payload> [server name] > (output to file)

ping -n 50 -l 1500 [server name] > c:\testping.txt

The example ping above does the following: Sends 50 packets, with a buffer size of 1500 (generally the default MTU packet size) and saves the output to c: as testping.txt