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Showing posts from August, 2012

ICMP Ping a Class C Network Subnet on Unix or Linux and return corresponding MAC Address

Ping a subnet by defining first three octets and return corresponding MAC Addresses for any IP addresses that respond to ICMP Ping on directly attached network. You may have come across this requirement but I use it very often to update the inventory and status of my network. Something I maintain and find very useful to audit the network, find anomilies and know what is allocated to what. Also useful if you manage MAC Address filtering on your Router. ------------------- Begin of script ./multiping ---------------------- #!/bin/bash echo "Usage: ./multiping [subnet e.g. 192.168.1]" CURR=1 SUBNET="$1" FILE=multiping.log touch $FILE function multiping() { ping -c1 -t1 $SUBNET.$CURR 2>&1 >/dev/null if [ "$?" -eq "0" ]; then echo $(arp $SUBNET.$CURR) >> $FILE fi } while [ $CURR -lt 255 ] ; do multiping & let CURR=$CURR+1 let MOD=$CURR%100 #this code is for prevent the saturation of the executable connections if [[ $MOD -eq...

Linux Stress Testing Tips and Tricks

Disk Stress & Fault Test Create a 1GB file with 1000 x 1MB blocks. localhost:/$ dd if=/dev/zero of=/tmp/temp-file.tmp bs=1M count=1000 Output expected with time it takes and disk write speed in MB/s 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB) copied, 6.83976 s, 153 MB/s Now you can run a md5sum check to see if the infomration in memory and disk appears correctly and if all md5sums identify any mismatch which would indicate a faulty disk or RAM. localhost:/$ for i in {1..5}; do md5sum /tmp/ temp-file.tmp ; done Output usualyl expected in below format e5c834fbdaa6bfd8eac5eb9404eefdd4  /tmp/ temp-file.tmp e5c834fbdaa6bfd8eac5eb9404eefdd4  /tmp/ temp-file.tmp e5c834fbdaa6bfd8eac5eb9404eefdd4  /tmp/ temp-file.tmp e5c834fbdaa6bfd8eac5eb9404eefdd4  /tmp/ temp-file.tmp e5c834fbdaa6bfd8eac5eb9404eefdd4  /tmp/ temp-file.tmp CPU Stress Test Output a string repeatedly until killed and direct the output to nothing will consume ver...