Tuesday, November 13, 2007
"Wait" command in Windows
: ping 127.0.0.1 -n 5 -w 5000 > nul
this command will do a wait for 5 secs.
Could be usefull
Wednesday, August 1, 2007
Remove Sendmail
Here's how to remove sendmail from your system.
Use it "at your on risk"
- Check for sendmail in /etc/init.d/
# ls -la /etc/init.d
# chmod -x /etc/init.d/sendmail - remove the execute
- Find sendmail in your boot scripts. It's usually in either /etc/rc or
/etc/init.d/sendmail. It looks like
sendmail -bd -q15m
-q15m means that it should run the queue every 15 minutes; you may
see a different number. Comment out this line.
- Kill the sendmail daemon. You should first kill -STOP the daemon; if
any children are running, you should kill -CONT, wait, kill -STOP
again, and repeat ad nauseam. If there aren't any children, kill
-TERM and then kill -CONT.
- Check whether you have any messages in the sendmail queue,
/var/spool/mqueue. If you do, you will have to try flushing them with
sendmail.bak -q. If necessary, wait a while and run sendmail.bak -q
again. Repeat until the queue is empty. This may take several days.
or delete the messages :)
# rm /var/spool/mqueue/*
# rm /var/spool/mqueue-client/*
- Check the crons
# ls -a /etc/cron*
- check if there are any sendmail files
- and rename or delete them
- Remove the setuid bit on the sendmail binary, to prevent local users
from gaining extra privileges through sendmail's security holes. The
binary may be at several different locations:
# chmod 0 /usr/lib/sendmail
# chmod 0 /usr/sbin/sendmail
# chmod 0 /usr/lib/sendmail.mx
- Move the sendmail binary out of the way:
# mv /usr/lib/sendmail /usr/lib/sendmail.bak
# mv /usr/sbin/sendmail /usr/sbin/sendmail.bak
- Check and remove the users if you want:
# more /etc/passwd -- check for smmsp, smmta
# userdel smmsp -- delete the user smmsp
# userdel smmta -- delete the user smmta
Monday, July 23, 2007
Basics of Cisco Switch
Before you can administer the switch you are going to need some basic information:
-
What is the switches IP address or DNS name?
-
What is the username/password you can use to login?
-
What Ethernet switch port is the device in question connected to?
One option to configure the switch might be a web-based administration interface. If this is the case, basic configurations aren’t going to be that difficult and perhaps you don’t need much more help. On the other hand, GUI interfaces aren’t always available, but on Cisco IOS switches, the Cisco IOS always is. Plus, in a GUI interface, you won’t be able to do every possible configuration. In the command-line interface you will be able to perform every possible configuration. For that reason, I encourage you to use the IOS command-line interface. I will be performing these common switch administration tasks on the Cisco IOS command-line interface.
Showing the switch configuration
# show running-config
Showing interface port status
The quickest way to see the status of your switch ports is to use the:
# show interfaces status
Changing interface speed & duplex
Say that you see that interface Fa0/21 is set to auto (auto negotiate) for its speed but it needs to be set to 10Mb/sec. To change the speed of any port, you go to interface configuration mode and use the speed command, like this:
Once the speed is configured to 10Mb, you can verify it with the show interfaces fa0/21 status, like this:
As you can see, the speed is now set to 10.
To change the duplex of a port, you perform the same steps but use the duplex command. Duplex can be set to auto, full, or half.
Enabling and disabling interfaces
Notice how when the port was shutdown, console messages appear that told you the administrative state had changed to down, and the line protocol changed to down. When the port was enabled (no shutdown), the link went down, then the line when up, then the line protocol changed to up.
You could now do a show interfaces status to see the state of the interface.
Sunday, July 22, 2007
Tips and Tricks WinXp
The netsh command on windowsXP can be used to do many things, some examples
To create a simple batch file for starting/stoping winxp firewall
Example:
Run: cmd.exe
c:\copy con fire.bat
netsh firewall set opmode disable | or enable ----- start or stop the firewall
^Z and enter -- saves the batch
Other examples:
Run: cmd.exe
c:\netsh firewall add portopening TCP 80 webserver ----- open port 80
c:\netsh firewall delete portopening TCP 80 ---- delete the rule