iptables -D (Chain Name) ( RuleNum)
eg.
iptables -D FORWARD 1
You can delete all rules from filter chain by typing :
iptables -F
or from nat table
iptables -F -t nat
Create a Self Signed Certificate :
1. Generate A Server Key : #openssl genrsa -des3 -out server.key 4096
2. Generate the Signing Request using the key above #openssl req -new -key server.key -out server.csr
3.Sign the certificate signing request. #openssl x509 -req -days 365 -in server.csr -signkey server.key -out server.crt
4. Now create a version of key that doesn't need a password : openssl rsa -in server.key -out server.key.insecure mv server.key server.key.secure mv server.key.insecure server.key
Generating Your Own Certificate Authority :
In order to create your own CA and sign a server certificate with it. Note: Common name of the CA and the Server Certificates must not match.
Steps :
1. Use IP address if you dont have the FQDN.
openssl genrsa -des3 -out ca.key 4096 openssl req -new -x509 -days 365 -key ca.key -out ca.crt
2.Generate a Server key and request for signing :
openssl genrsa -des3 -out server.key 4096 openssl req -new -key server.key -out server.csr
3.Sign the Certificate signing request with the Self created Authority
openssl x509 -req -days 365 -in server.csr -CA ca.crt -CAkey ca.key -set_serial 01 -out server.crt
Optional : You can check the keys and certificates :
openssl rsa -noout -text -in server.key openssl req -noout -text -in server.csr
openssl rsa -noout -text -in ca.key openssl x509 -noout -text -in ca.crt
4. Remove password from server.key so that apache doesnot need password :
openssl rsa -in server.key -out server.key.insecure
mv server.key server.key.secure
mv server.key.insecure server.key
Finally : Copy the files and adjust apache..
SSLEngine on
SSLCertificateFile /etc/httpd/ssl.crt/server.crt
SSLCertificateKeyFile /etc/httpd/ssl.key/server.key
configure apache to listen to https :
Listen x.x.x.x:443
LoadModule ssl_module modules/mod_ssl.so
configure SSL
Virtual Host : DocumentRoot "/var/www-ssl/html"
ServerName xxx.xxx.xxx.xxx:443
Now Restart Apache and you have ssl working on your site.
Vnc Installation Without Monitor
Packages Required :
1.vnc
2.vnc-server
3.Desktop Environment KDE or GNOME
Configuring VNC :
1. Add users like normal users.
2. login to each users
3. create password by running vncpasswd
4. It creates .vnc folder
5. Edit /etc/sysconfig/vncservers, and add the following to end of the file
VNCSERVERS="1:amitn 2:someuser"
VNCSRVERARGS[1]="-geometry 640×480" ( for amitn )
VNCSRVERARGS[2]="-geometry 640×480" ( for someuser)
VNCSRVERARGS[1]="-geometry 800×600"
6.Create Xstartup scripts by starting and stopping vncserver as root
/sbin/service vncserver start
/sbin/service vncserver stop
7. Login to each user and edit xstartup script
8. vi .vnc/xstartup
#!/bin/sh
# Add the following line to ensure you always have an xterm available.
( while true ; do xterm ; done ) &
# Uncomment the following two lines for normal desktop:
unset SESSION_MANAGER
exec /etc/X11/xinit/xinitrc [ -x /etc/vnc/xstartup ] &&
exec /etc/vnc/xstartup [ -r $HOME/.Xresources ]
&& xrdb $HOME/.Xresources xsetroot -solid grey vncconfig -iconic & xterm -geometry 80×24+10+10 -ls -title "$VNCDESKTOP Desktop" & startkde &
Rsync is a nice utility to synchronize files and folders between two servers securely and efficiently. It only copies the difference so making the process much faster and efficient.
Ok, here i will show you how to setup rsync.
1. Download the rsync package. Click Here
2. Untar the package and enter into the directory.
3. ./configure
4. make
5. Make install
6. Create the configuration file for rsync
#vi /etc/rsyncd.conf
#/etc/rsyncd.conf
secrets file = /etc/rsyncd.secrets
motd file = /etc/rsyncd.motd #Below are actually defaults, but to be on the safe side...
read only = yes
list = yes
uid = nobody
gid = nobody
[out]
comment = comment for your directory
path = /home/rsync/out
[confidential]
comment = For your eyes only
path = /home/rsync/secret-out
auth users = amit,nishant
hosts allow = 192.168.100.100
hosts deny = *
list = false
#save the file.
Now create a script for starting and stopping the daemon :
#vi /etc/init.d/rsyncd
#!/bin/sh
# Rsyncd This shell script takes care of starting and stopping the rsync daemon
# description: Rsync is an awesome replication tool.
# Source function library.
. /etc/rc.d/init.d/functions
[ -f /usr/bin/rsync ] || exit 0
case "$1" in
start)
action "Starting rsyncd: " /usr/bin/rsync --daemon
;;
stop)
action "Stopping rsyncd: " killall rsync
;;
*)
echo "Usage: rsyncd {start|stop}"
exit 1
esac
exit 0
# Now create a symbolic link at /etc/rc.d/rc3.d
#cd /etc/rc.d/rc3.d
#ln -s /etc/init.d/rsyncd rsyncd
Now start rsyncd at the server side
#service rsyncd start
You can issue this command to copy the files :
rsync -avz amit@server name or ip::out /home/rsync/in
or you can use the following command to use ssh
rsync -avz -e ssh rsync@server_ip:/home/rsync/out/ /home/rsync/from_remote
Now you can set this up in a cron.
If you need to get a value for the selected item in a combo box you can use the following function :
onchange=”alert(this.options[this.selectedIndex].text)
if you need the value then just replace text with value .
For example, if you want to redirect the page based on combobox selection :
onchange=”window.location=”http://someadress”+(this.options[this.selectedIndex].text)
It is possible to bind more than one ip address on a single network interface card in linux.
copy your existing network card configuration file as shown:
#cd /etc/sysconfig/network-scripts
#cp ifcfg-eth0 ifcfg-eth0:1
>>ifcfg-eth0 looks like this :
# File: ifcfg-eth0
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=static
IPADDR=192.168.100.1
NETMASK=255.255.255.0
BROADCAST=192.168.100.255
NETWORK=192.168.100.0
HWADDR=00:8A:4E:34:CF:84
Change the device name and the ip address parameters
File : ifcfg-eth0:1
and
DEVICE=eth0:1
#save the fiel and then restart the network
#service network restart