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How to install iperf3 on CentOS 7 offline

To install iperf3 on CentOS 7 in offline mode, you need to download two files one for EPEL libraries and one for iperf3, upload to your CentOS machine with WinSCP and then follow two command (given below) to install the iperf3.

Click here to download the latest version of iperf3
Click here to download the latest EPEL library file
EPEL libraries file should have name like this epel-release-*.rpm Upload both files to your CentOS machine, say in /tmp folder Take SSH Session of CentOS Machines
Go to the folder where you uploaded both files, i.e. /tmp
Install EPEL release rpm with following command # rpm -Uvh epel-release-*rpm
Install iperf3 with following command #rpm -Uvh iperf3-*.rpm
iperf3 has been successfully installed on your CentOS machine.
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Configure fencing on RedHat for Cisco UCS

How to configure fencing on RedHat or CentOS Linux installed on Cisco Unified Computing System UCS blade Servers.
Below is a single command to shut a blade server when configuring fencing on Linux
Command to enter on redhat machine

#fence_cisco_ucs -a UCS-Domain-VIP -l User-ID -p ******** -z -n org-root/SERVICE-PROFILE-NAME -o status

replace above in blue font with the following information

UCS-Domain-VIP                 =              UCS manager IP
User-ID                                   =              User ID
******                                       =              password of User ID
SERVICE-PROFILE-NAME =              replace it with the service profile name of the server

Create a new ID in UCS Manager with only power on/off rights, and use that ID to send fencing poweroff command to the UCS Blades from RedHat Linux

ESXi vmnic shows 20gb or 40gb instead of 10gb On UCS

After configuring UCS Service profile, installing VMWare ESXi and configuring Nexus 1000v, i found VMWare vmnics were showing 20 gbps per nic. It was little confusing for me as each UCS Server port from blade to Fabric Interconnect should show 10 gbps. I started exploring it and found an interesting design of Cisco UCS VIC Cards 1340/1380 or UCS Port expander.
As you can see there is hardware port channel between the virtual nics, and the outward ports connected to the IO modules.
 As you can see it depends upon different type of connectivity between VIC cards and IO Modules, if you are connecting VIC 1340 without port expander then hardware port-channel see only two 10 gig interfaces connected to it and it presents 20 gig connections to each server Ethernet link, vmnic on ESXi in our case. And if a port expander is connected then the hardware port-channel sees four 10 gig interfaces connected to it so it represents as 40 gig connection for each Ethernet link down the Server. This bandw…

What is Secure Shell (SSH) and how to configure SSH in Cisco Devices

What is Secure Shell (SSH) and how to configure SSH in Cisco DevicesWhat is Secure Shell (SSH) Secure Shell is a protocol that can be used in the place of well known Telnet protocol to remotely connect to your Cisco Router or Switch. Telnet has long been used to manage network devices; however, Telnet traffic is sent in clear text. Anyone able to sniff that traffic would see your password and any other information sent during the Telnet session. Secure Shell (SSH) is a much more secure way to manage your routers and switches. It is a client/server protocol that encrypts the traffic in and out through the vty ports.
Cisco routers and switches can act as SSH clients by default, but must be configured to be SSH servers. That is, they can use SSH when connecting to another device, but require configuration before allowing devices to connect via SSH to them. They also require some method of authenticating the client. This can be either a local username and password, or authentication with …

Cisco CLI Command to Quickly List out Availale Interfaces and their status

The Cisco CLI Command which i often use when i am running a New Cisco Device (Router or a Switch) to quickly list out the available interfaces and to check their status up or down. See the command and the output below
Router#show interfaces description
Interface Status           Protocol Description
Fa0/0     up                     up
Fa0/1     admin down     down
Se1/0     up                     up
Se1/0.1   up                    up
Se1/0.2   up                    up
Se1/1     admin down     down
Se1/2     admin down     down
Se1/3     admin down     down

Cisco IOS different names with different Features

Different types of Cisco IOSs with different features are available for download with different names.
Cisco IOSs can be selected and downloaded as per the features they provide. Here is the brief definition of Eight Different types of IOSs having specific features. Choose what you need for you company by understanding with IOS name.
• IP Base
IP Base without Crypto-Entry level Cisco IOS Software image (Classic IP Data + trunking and DSL)
• IP Voice
IP Voice without Crypto, Adds VoIP, VoFR to IP Base (Adds Voice to Data)
• SP Services
Adds SSH/SSL, ATM, VoATM, MPLS, etc. to IP Voice (Adds SP Services to Voice & Data)
• Advanced Security
Adds Cisco IOS FW, IDS/IDP, NAC, SSH/SSL, IPsec VPN, etc. to IP Base (Add Security/VPN to Data)
• Enterprise Base
Enterprise Base without Crypto, Adds Enterprise Layer 3 routed protocols (AT, IPX, etc.) and IBM support to IP Base (Add Multiprotocol Services to Data)
• Enterprise Services
Enterprise Services without Crypto4-Adds full IBM support, Service Provide…

Telnet Client is Disabled Enable it to use it from this application

This is a Cisco Network Assistant (CNA) error when you want to telnet any Cisco Devices from within CNA.
Solution to remove this error is related to Windows 7 or Windows Vista. First of all you need to Add TELNET program from Control Panel, which by Default is not added in fresh installation of Windows 7.For adding and using Telnet Program in Windows 7, Click Start > Control Panel > Uninstall a Program > Turn Windows Features On and OFF > Scroll to TELNET and Select it > Press OK After Adding Telnet Program into the Windows 7 you need to Copy Telent.exe from C:\Windows\System32 folder and paste it to C:\Windows\SysWOW64\ Now you should not get the same error.