Saturday, July 27, 2013

NTP Cisco - Juniper MD5 Authentication



In this example I'm going to configure Cisco router to by NTP server and the source for his time will be local configured time, best practice is to use more then one NTP server and use GPS Network Time Server (hardware or software)

 
R1#show clock
*00:06:25.899 UTC Fri Mar 1 2002
R1#clock set 21:51:50 22 july 2013  
- Use clock set command

SolarWinds SFTP & SCP Server Running Problem



I download and installed the SolarWinds SFTP & SCP Server, you can find lots of free network tools at theirs site. 
For free tolls follow the link http://www.solarwinds.com/downloads/
But I had to point to the problem that I have lunching the SFTP & SCP server. When I run the application everything looks just fine, except the service is not running and cannot be started.

See pictures below:




Friday, July 12, 2013

Oracle VM And Windows Server 2012 Nic Problem



I installed Windows Server 2012 for testing in Oracle VM, and during installation I used default configuration for VM. When I logged on and try to configure network settings there wasn't an network adapter at all.


Thursday, July 11, 2013

Backup Configuration Using Kron Schedule



You want to make sure your router automatically saves its configuration on scheduled time? For that purpose you can use kron command on router or switch.

But (yes, there is a but :)) , first you have to configure accurate time on router, to do that use clock set or use ntp server command.

In this lab I'm using TFTP server (tftpd32) for backing up my config, you can use FTP or SCP and kron command to automatically backup configuration.


Here you can download TFTP, SFTP and SCP servers without any fees. 


After setting the clock, disable pop-up questions when using copy command, those questions are appears beside you supply the complete source and destination file name in the command line, the IOS  will still ask you a question about ip address of TFTP server and file name destination.

To solve the problem use file prompt quit command (the default value is noisy), after that you can start configuring kron scheduler.




Step 1.
HLabR1(config)#kron policy-list SAVECONFIG
HLabR1(config-kron-policy)#cli copy running-config tftp://10.2.0.2/config
HLabR1(config-kron-policy)#exit
HLabR1(config)#kron occurrence SAVE at 21:51 Sun recurring
HLabR1(config)#policy-list SAVECONFIG


Step 2.

Use debug kron all to see what  going to happen at scheduled time.



Jul  7 21:51:16.656: Kron CLI return 0'


**CLI 'copy running-config tftp://10.2.0.2/config':

!!1253 bytes copied in 3.268 secs (383 bytes/sec)'

Jul  7 21:51:16.664: Major 4, Minor 7

Jul  7 21:51:16.664: Respond to end of CLI Process






Use show kron schedule command to see when will run again.
 



Saturday, May 11, 2013

SSH Optional Configuration And Testing



I won't write about how is SSH secure than Telnet and that is recommended practice for remote administration network devices, that all Telnet traffic is forwarded in plain text etc, etc, because you already know that.

I will point for optional configuration that is equally needed (in my opinion), but I will also point to steps that you must configure first.

Step 1: Configure the IP domain name
Step 2: Generate one-way secret keys
Step 3: Verify or create a local database entry
Step 4: Enable VTY inbound SSH sessions

Optionally you can configure SSH version, timeout period and number of authentication retries.

You can configure the time that router waits for SSH client to respond for session by configuring command ip ssh time-out seconds in global configuration mode, default value is 120 seconds.

Also you can control how many attempts user can retries for password during connection with SSH client. The command is ip ssh authentication-retries value , by default user has tree attempts before being disconnected.
During configuration and testing I notice that real numbers of attempts is configured value plus 1, if you enter ip ssh authentication-retries 2  user will have tree times to repeat the password. I tried with value from 0 to 5 and every time I tried to connect I had one plus attempt beside configured value.
As you can see on screen shots and running SSH configuration you get one plus attempt for free. :)

Thursday, March 21, 2013

Best Practice Access List Branch Office Router (Firewall)


At Branch office you will not always use ASA for security and VPN connectivity with Central office, best way is to use router that you already have at Branch office using Access control list.

 



This approach is best for this scenario, you can change, add or modify for your needs.

Monday, November 26, 2012

How To Configure VPN Site-to-Site using CiscoCP – GNS3

This is network lab I used to configure VPN in GNS3. I used my LAN to simulate the Internet and the network is 10.143.88.0 /24, and two LAN’s I want connect via VPN, 192.168.100.0/24 and 192.168.200.0/24.



Sunday, September 30, 2012

How to remove caps/num lock notifications




Every time when I press Caps Lock or Num Lock on keyboard notification balloon pop-up in right low corner of the screen that it’s been turned on/off. It is annoying and it’s disabled me from typing for a couple of seconds. So I decided to turned off, process responsible for notification is QLC Controller.

You can turn off from Task Manager, but every time you Log Off or Turn Off your computer it’s started again. The best way is to turner of from Startup. To do so, start MSCONFIG from Run and from Startup tab and uncheck HP Hotkey Support. 



This will solve problem permanently.