0x8a IPTABLES - DROP PING

iptables -A INPUT -p icmp --icmp-type echo-request -j DROP
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0x76 LINUX - EMERGENCY REBOOT

If you find yourself in this situation (and I hope you won’t!), you have some options to get your way with a misbehaving server remotely. You can force an immediate reboot with the following:

echo 1 > /proc/sys/kernel/sysrq 
echo b > /proc/sysrq-trigger

WHOA THERE! This is pretty much the same as pressing the reset button on the server (if equipped). No daemons will be shut down gracefully, no filesystem sync will occur, and you may get the wrath of a fsck (or worse, a non-booting server) upon reboot.

linux admin

 

0x75 TCPDUMP - GREP 80 REQ

sudo tcpdump -A -s 10240 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)' | egrep --line-buffered "^........(GET |HTTP\/|POST |HEAD )|^[A-Za-z0-9-]+: " | sed -r 's/^........(GET |HTTP\/|POST |HEAD )/\n\1/g' 
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0x6c GIT - ADD REMOTE

So, firstly setup the remote repository:

ssh git@example.com
mkdir my_project.git
cd my_project.git
git init --bare
git update-server-info # If planning to serve via HTTP

On local machine:

cd my_project
git init
git add *
git commit -m "My initial commit message"
git remote add origin git@example.com:my_project.git
git push -u origin master
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0x6b XEN - BRIDGE SETUP

So, for the VM we set a bridge. To do that we need to have bridge-utils package installed (yum install bridge-utils) and set-up the br0 bridge. There’s no need to set an IP address on the bridge as we only need to set a static route on it.

/etc/sysconfig/network-scripts/ifcfg-br0 would look like this:

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