Monthly Archives: November 2015

Ping request and response messages

Ping “Packet InterNet Groper” (operates by sending Internet Control

Message Protocol (ICMP) echo request packets) is a network

administration software utility used to test the reachability of a

host on an Internet Protocol (IP) network and to measure the round-

trip time for messages sent from the originating host to a destination

computer and back.

Destination host unreachable: The device you are trying to PING is

down or is not operating on the network. This could also mean you will

have to recheck the settings on your device to make sure the host is

correctly configured and also check that the routing is working

properly because a route to the destination system could not be found.

If you are trying to PING something outside of your local network,

check if gateway address is correct.

Bad IP address: An invalid IP address was entered on the command

prompt line. The IP address must be written in a dotted decimal

format, for example 127.0.0.1. Check that the IP address is correct.

Destination net unreachable: The targeted gateway to the IP

address written in the command prompt window could not be reached.

Check your computer gateway to be correct and routing table to the IP

address.

Destination specified is invalid: An invalid address has been

written in the command prompt window. Make sure the format of the

address is correct and then try again.

Request timed out: The ping command has timed out because there

was no reply from the targeted device. First check if your TCP/IP

stack is functioning correctly by pinging 127.0.0.1 . This doesn’t

mean that your network card is working properly. Now ping your default

gateway and make sure you have connectivity. Ping the next hop after

the gateway or a device before our faulty device, like a router

interface. If you have connectivity this could mean our faulty device,

the one we get replies with “request timed out” from has a problem or

may be down and not the network channel to the device. If you get

reply from another device on the way, but not from the host we are

troubleshooting, this could also mean there is no route back to your

device. Note: Destination Net Unreachable will show the IP address of

the router that tried to route a packet but couldn’t find a valid

route.

TTL expired during reassembly: The TTL value defines the number of

maximum hops a packet may live inside a network without reaching its

destination, before being discarded. It’s actually the number of

routers a packet may pass through network to destination, before being

dropped. This means the TTL value was too small and it failed to

reassembly either at the destination or on the local machine. Use -i

parameter for PING command to increase TTL value.

TTL expired in transit: The TTL value defines the number of

maximum hops a packet may live inside a network without reaching its

destination, before being discarded. It’s actually the number of

routers a packet may pass through network to destination, before being

dropped. This means the TTL value was too small to reach the target

and it failed on the way by being dropped. Use -i parameter for PING

command to increase TTL value.

Hardware error: Ping your loop-back address 127.0.0.1 to verify

that your TCP stack is working properly. If you can ping this, check

the cable. Else you will have to troubleshoot the TCP stack and

network interface card.

 No resources: Means exactly what it says but it targets RAM memory

most of times. Close some applications like the ones you don’t need

right now and try again. If this fails, reboot your computer. Will

work after.

Microsoft Robocopy

Robocopy, or “Robust File Copy is an advanced copy utility with has the feature to automatically resume file transfer on error or network disruption, or recover from terminated file copying . It also can preserve all of the file properties and information, including date and time stamps, security access control lists (ACLs) and more while replicating the file.

Robocopy came built-in in Windows operating system such as Windows Vista, Windows 7, Windows 8, Windows 8.1, Windows 10 and Windows Server with command line interface only.

Syntax
robocopy <Source> <Destination> [<File>[ …]] [<Options>]

Robocopy GUI really simplify the process,having many options consolidated in a graphical interface lets you specify your source and target paths.

For example, this tool is multithreaded, allowing you to create a Robocopy script, execute it, and begin creating another one while your first script is still running. It also allows you to save your scripts (even if you don’t actually execute them) so that you can create a library of common scripts or share them with your colleagues. And most importantly, Robocopy GUI allows you to save your default settings so you don’t have to start from scratch every time.

Synatax and parameter
https://technet.microsoft.com/en-us/library/cc733145.aspx

Userguide

Microsoft Robocopy GUI Users Guide

robocopy

references
https://technet.microsoft.com/en-us/library/cc733145.aspx

Nearline Storage- An archiving service from Google Cloud

Nearline is like Amazon Glacier archiving and storage service.It is cheap,faster recovery and  on-demand I/O service with large amounts of data.

Google also launched Cloud Storage Transfer Service(earlier Online Cloud Import)offers 100 PB of free storage in Nearline for up to six months for customers

who switch from any other cloud provider or on-premises environments to Google Cloud Storage.

Both Nearline and Glacier charge same amount (penny/GB) for a month to store data, but recovery times in seconds compares hours in Glacier.

Read more about Nearline
https://cloud.google.com/storage/docs/nearline?hl=en
https://cloud.google.com/storage-nearline/

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