Posts Tagged ‘ Unix ’

SSH Login without password using public key authentiation

August 23, 2012
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On Computer A Create the public and private keys using the command ssh-keygen # ssh-keygen -t rsa Generating public/private rsa key pair. Enter file in which to save the key (/root/.ssh/id_rsa): Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /root/.ssh/id_rsa. Your public key has been...
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Unable to login to remote server via ssh

May 18, 2011
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A funny thing happened to one of my Red Hat 5 Enterprise servers after applying the errata. I rebooted the servers as usual after applying the updates, and they came up just fine. But unfortunately I was not able to logon remotely via ssh to a server. I tried various different accounts including root,...
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How to create a new superuser in Linux

May 17, 2011
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The administrative account ‘root’ is the most powerful user in Linux and Unix. This account is created by default during installation of the operating system. Most security consultants will recommend that the root account be deleted or renamed. This is to make it harder for a hacker to find out what a valid user...
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Nslookup resolves address but ping is unable to resolve hostname on Unix server

November 17, 2010
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I came across this issue on my newly built Solaris 10 server. I was able to ping a remote machine by Ip address, but not by its hostname. This indicated that I had the correct route and gateway. Using nslookup and dig I verified that the DNS servers were resolving the hostname to IP...
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How to map to a remote NFS directory from a VMware ESX 4 server.

November 16, 2010
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I ran into this error while trying to mount a NFS directory on a remote server from my Vmware ESX4 server. My Vmware esx server is called esx4-server and the remote NFS server is called remote-server. I executed the mount commant and got the below error. # mount -t nfs remote-server:/home/andrew/mnt mount.nfs: Input/output...
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Sun Sparc commands to power on and boot up the server.

November 15, 2010
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Booting up the Sun Sparc M3000 server. After logging into the XSCF console, power on the server. XSCF> poweron -d 0 DomainIDs to power on:00 Continue? :y Switch to the server console. XSCF> console -d 0 Connect to DomainID 0? :y Devalias will list all devices which can be booted. {0} ok devalias...
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Creating RDM to LUN (SAN) mapping on VMware ESX 4, Vcenter.

August 6, 2010
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In the past I have written articles about how to create a RDM to LUN disk mapping for VMware ESX 3. http://www.gamescheat.ca/2009/10/scripts-to-automate-the-process-of-identifying-and-compiling-an-rdm-to-lun-mapping-list-for-vmware-esx-30/ and http://www.gamescheat.ca/2009/10/how-to-identify-and-compile-an-rdm-to-lun-mapping-list-for-vmware-esx-30/ The procedure to identify the path for the RDM (raw disk mapping) to LUN (disk on SAN) on Vmware ESX 4 is different from Vmware Esx 3. There are a...
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Booting up Solaris 10 from a SAN replicated LUN on a different Sun SPARC server

July 9, 2010
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The quickest way to recover from a total disaster is to have some sort of replication implemented. There are two different methods of real-time replication, hardware and software. My experiences with software replication such as Symantec Veritas Volume replicator for AIX was not pleasing. It required constant maintenance and troubleshooting. The best is hardware...
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How to get the network card speed in Solaris 9

May 12, 2010
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To determine the network card speed in Solaris 9 use the ndd utility. First list the NIC installed and active on the Solaris 9 server. # ifconfig -a lo0: flags=1000849 mtu 8232 index 1 inet 127.0.0.1 netmask ff000000 hme0: flags=1000843 mtu 1500 index 2 inet 162.10.1.11 netmask ffff0000 broadcast 162.10.255.255 ether 8:0:20:c4:8c:87 There is...
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How to list the status of swap in Solaris

February 26, 2010
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List the status of all swap areas. # swap -l swapfile dev swaplo blocks free dev/dsk/c0t0d0s1 32,9 16 8425712 8425712 The output has five columns: path The path name for the swap area. dev The major/minor device number in decimal if it is a block special device; zeroes otherwise. swaplo The swaplow value for...
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