OpUtils

Knowledge Base

Problem

You get an error as "Unreachable Host " when attempting to add a device in Oputils.

Cause

This is a common error message that you get when you add a device in most of the tools in OpUtils. When a device is added, the following checks are performed:

1. When you add the device using its DNS name, OpUtils will first resolve its IP address.
2. Once the IP is resolved or when you add the device using its IP address, it sends an ICMPpacket to that device to check for its availability. If there is no response from the device, this error message is shown

The following could be the reasons:

1. The device is down.
2. When there is no network route to that device from the computer where OpUtils is installed
3. ICMP Ping has been blocked by the Windows Firewall.
4. If its a switch/router, the Ping has been disabled in the Access List.

Resolution

Bring Up the Device

Check whether the device is down and start the device. From the computer where OpUtils is installed, try pinging the device from the command prompt and check whether you get a response.

Check the Network Route

Check using the Trace Route tool whether you are able to reach the device. The trace route will show the network path to that device with the response time in each hop.You can either use the Trace Route tool of OpUtils or the tracert <IP Address> command from the command prompt

If you are not able to reach the device, use the route ADD command to add the gateway server/router to reach the device.

Check and Clear the Firewall/Access Lists

1. If the Firewall running in the device is blocking the ICMP packets, configure it to allow ICMP packets from the computer running OpUtils.
2. If the device is a Switch or a Router, check the Access List and add the IP Address of the computer running OpUtils to allow the ICMP packets.

Applies to: Network Monitor, MAC Address Resolver, DHCP Scope Monitor, Bandwidth Monitor

Keywords: unreachable host, device not reachable, no network path, firewall, access lists, ping disabled

Knowledge Base