Cisco TSHOOT – Top 10 Show Commands

Cisco Router Tips
Top 10 'show' Commands by Tom Lancaster

One of the most important abilities a network administrator can have is the know-how to get information out of his network devices so he can find out what's going on with the network. In most networks, the staple of information gathering has been the "show" commands. Here are my top ten commands to know and love:

1. show version: Start simple; this command gives uptime, info about your software and hardware and a few other details.
2. show ip interface brief: This command is great for showing up/down status of your IP interfaces, as well as what the IP address is of each interface. It's mostly useful for displaying critical info about a lot of interfaces on one easy to read page.
3. show interface: This is the more popular version of the command that shows detailed output of each interface. You'll usually want to specify a single interface or you'll have to hit 'page down' a lot. This command is useful because it shows traffic counters and also detailed info about duplex and other link-specific goodies.
4. show ip interface: This often overlooked command is great for all the configuration options that are set. These include the switching mode, ACLs, header compression, ICMP redirection, accounting, NAT, policy routing, security level, etc. Basically, this command tells you how the interface is behaving.
5. show ip route: This indispensable command shows your routing table, which is usually the primary purpose of the box. Get to know the options on this command.
6. show arp: Can't ping a neighbor? Make sure you're getting an arp entry.
7. show running-config: This is an easy one. It tells you how the box is configured right now. Also, "show startup-config" will tell you how the router will be configured after the next reboot.
8. show port: Similar to the show interface command on routers, this command gives you the status of ports on a switch.
9. show vlan: With the trend toward having lots of VLANs, check this command to make sure your ports are in the VLANs you think they are. Its output is very well designed.
10. show tech-support: This command is great for collecting a lot of info. It basically runs a whole bunch of other show commands, and spits out dozens of pages of detailed output, designed to be sent to technical support. But, it's also useful for other purposes.

Taken From: http://www.thenetworkadministrator.com/ciscoroutertips.htm

Remote Applications via X11 - Easy Way (over ssh)

Here I will show you how to interact with applications remotely. This is quite useful when you have for example an Ubuntu Server that doesn't have a graphical environment (Gnome or KDE) and a Desktop that has and you need to use some graphical applications on the Ubuntu Server but you can't because you don't have a graphical environment.

So whit this you can show and interact with the graphical applications on the Ubuntu Server, using your Desktop's, graphical environment. So in the X11 world you have the following:

Ubuntu Server - X11 Client --> Application is executed
Ubuntu Desktop - X11 Server --> Application is shown

It's a bit confusing at first, that your Ubuntu Server is your X11 Client, and you Desktop is the X11 Server.

Note: this was tested on Ubuntu 8.04 and 9.04.

X11 Server - Where the remote apps will be shown
===================================

my_user@my_desktop:~$ ssh -X root@remote_server
root@remote_server:~$

Now you have a what looks like a normal ssh remote terminal on the "remote_server". But when you execute an graphical apps on the remote server it will be displayed on your desktop, for example:

root@remote_server:~$ gedit

With this you can make a text file on your machine tha will be saved on the remote server.

If you want ssh to always act like this, have the following line in your /etc/ssh/ssh_config:

ForwardX11 yes

With this method all the data over the network will be encrypted, because of ssh, but if you want to kick it old school, whit no encryption an a lot more complicated using X11 directly, you can check the post "Run Applications Remotely via X11 - Hard Way"

Based on: http://wiki.linuxquestions.org/wiki/X11_forwarding_with_OpenSSH

Remote Applications via X11 - Hard Way

Here I will show you how to interact with applications remotely. This is quite useful when you have for example an Ubuntu Server that doesn't have a graphical environment (Gnome or KDE) and a Desktop that has and you need to use some graphical applications on the Ubuntu Server but you cant because you don't have a graphical environment.

So whit this you can show and interact with the graphical applications on the Ubuntu Server, using your Desktop's, graphical environment. So in the X11 world you have the following:

Ubuntu Server - X11 Client --> Application is executed
Ubuntu Desktop - X11 Server --> Application is shown

It's a bit confusing at first, that your Ubuntu Server is you X11 Client, and you Desktop is the X11 Server.

Note: this was tested on Ubuntu 8.04 and 9.04.

X Server - 192.168.1.68 (Where the remote apps will be shown)
=======================================
## Allow that the remote applicatilõns to be show on the X11 Server #####
$ sudo gedit /etc/gdm/gdm.conf

DisallowTCP=true
change it to
DisallowTCP=false


## Reboot to load the new gdm.conf file #####
$ sudo reboot


## Check if the X Server TCP Connections ######
$ netstat -natp |grep :6000

(Not all processes could be identified, non-owned process info
will not be shown, you would have to be root to see it all.)
tcp 0 0 0.0.0.0:6000 0.0.0.0:* LISTEN -
tcp6 0 0 :::6000 :::* LISTEN -


## Add permission for the remote X Client applications #####
## to be shown locally this is temporary, when you #####
## reboot, you must do this again #####
$ sudo xhost 192.168.1.71

## Find the id of the display you are in currently, #####
## and were we see the remote apps, from the X Clinet #####
$ echo $DISPLAY
:0.0


X client - 192.168.1.71 (Where the remote apps will be executed)
========================================

In order to show an application remotely you should use one of the options bellow, where 192.168.1.68 is the IP of the remote computer were the applications will be shown and 0.0 is the id of the graphical terminal on that computer, found earlier, were the remote applications will be displayed.

In this example we execute the application "nautilus", you should change it to the application you want to see remotely.
$ sudo DISPLAY=192.168.1.68:0.0 nautilus
or
$ sudo export DISPLAY=192.168.1.68:0.0
$ nautilus

some applications will not work with the first option so try the second.

After executing one of the two options above, the applications
will be running locally on the X Client (192.168.1.71) but displayed remotely on X Server (192.168.1.68), the applications will not be able to see or use anything on the X Server, there you can only interact with it, and all the resources it may use are from the X Client (local machine).

For example if you replace "nautilus" with "gedit", write something on it and save it the file will be saved on the X Client and not on the X Server were you are interacting with it.


With this method all the data over the network will not be encrypted, if you want a method with encription and a lot easyer using X11 over ssh, you can check the post "Run Applications Remotely via X11 - Easy Way (over ssh)"


Inspired on:

http://ubuntuforums.org/showthread.php?t=162566
http://www.cisl.ucar.edu/docs/ssh/guide/node29.html
http://www.hackinglinuxexposed.com/articles/20040513.html
http://www.linuxquestions.org/questions/linux-newbie-8/how-do-i-restart-x-without-rebooting-418785/
http://www.linuxplanet.com/linuxplanet/tutorials/857/3/
http://www.codingdomain.com/linux/remote/x11/