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How to load an IOS onto a Cisco router using the ROMmon mode Solution To load an IOS onto a router using ROMmon mode via Ethernet cable: Start the TFTP server (make sure the file path is correct and that you allow both transfer and receive) Connect to the router via Ethernet cable (an Ethernet cable is preferred due to the large size of the file and the maximum speed that data can travel over the console cable) ¨ Before the IOS is loaded it is important to make sure that your router has enough memory to support the IOS. The router will allow an IOS to be loaded even if there is not enough memory, in this case a smaller IOS will have to be loaded. At the rommon prompt enter the following commands (commands are case sensitive, and the use of the directional arrows and tab auto complete function is not allowed): IP_ADDRESS=IP address of the Ethernet port IP_SUBNET_MASK=subnet mask of the Ether...

OpenSSL Command-Line HOWTO The openssl application that ships with the OpenSSL libraries can perform a wide range of crypto operations. This HOWTO provides some cookbook-style recipes for using it. Table of Contents Introduction How do I find out what OpenSSL version I’m running? How do I get a list of the available commands? How do I get a list of available ciphers? Benchmarking How do I benchmark my system’s performance? How do I benchmark remote connections? Certificates How do I generate a self-signed certificate? How do I generate a certificate request for VeriSign? How do I test a new certificate? How do I retrieve a remote certificate? How do I extract information from a certificate? How do I export or import a PKCS#12 certificate? Certificate Verification How do I verify a certificate? What certificate authorities do...

key skill for a system administrator is being able to deploy your own custom software. However, you first need to build an RPM package that contains your cus- tom software. This can seem like a large undertaking at first, but after a few times the process is pretty simple. To build an RPM, you must do the following: Create a directory hierarchy. Step 1. Copy or create your source code into the directory hierarchy. Step 2. Create a spec file. Step 3. Build the RPM. Step 4. The hierarchy that you create must meet the rpmbuild specification, which is com- posed of the following directories: BUILD Contains scratch space used to compile software RPMS Contains the binary RPM that is built SOURCES Holds the source code for the RPM SPECS Contains the spec file(s) (one per RPM) SRPMS Contains the source RPM built during the pro...

All Unix and Unix-like systems generate a metric of three "load average" numbers in the kernel . Users can easily query the current result from a Unix shell by running the uptime command: $ uptime 14:34:03 up 10:43, 4 users, load average: 0.06, 0.11, 0.09 The w and top commands show the same three load average numbers, as do a range of graphical user interface utilities. In Linux , they can also be accessed by reading the /proc/loadavg file. An idle computer has a load number of 0 and each process using or waiting for CPU (the ready queue or run queue ) increments the load number by 1. Most UNIX systems count only processes in the running (on CPU) or runnable (waiting for CPU) states . However, Linux also includes processes in uninterruptible sleep states (usually waiting for disk activity), which can lead to markedly different results if many processes remain blocked in I/O due to a busy or stalled I/O system. This, for example, includes processes blocki...