November 25, 2013
The router goes through a series of events every-time the router is powered on, from performing tests and loading IOS. For the ICND2 exam it is required that you can describe the boot process. Here are the events:
- Initially the router will undertake a POST, which tests to see if the Router is functional. POST is run and stored in ROM
- The Bootstrap program is run, its job is to find, locate and run the IOS software. First it checks the configuration register then the boot sequence is checked in NVRAM. By default IOS is loaded from FLASH
- IOS is loaded into RAM and it will check NVRAM for a working config called startup-config
- Once startup-config is found the file will now be loaded into RAM and is now known as running-config
If a startup-config is not found the router will send out a broadcast looking for a TFTP host containing a configuration file, when this fails the router will then load into setup mode.
Leave a Comment » | 
ICND2 Topics, Networking, Routers | Tagged: boot, ccna exam, Cisco router, cisco router boot sequence, Console, icnd2, iOS, ios software, nvram, post, power on self test, ram, rom, router boot | 
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Posted by Josh Gahan
October 1, 2013
The diagram below is the network in use:
Switch 3
FA0/1 – DP
FA1/1 – DP
Switch 1
FA1/1 – RP
FA0/1 DP
Switch 2
FA1/1 – RP
FA0/1 – DP
Switch 0
FA0/1 – RP
FA1/1 – ALTN
The lab for this example can be downloaded by clicking here
Leave a Comment » | ICND2 Topics, IOS Commands, Networking, Protocols, Switches, Troubleshoot | Tagged: ccna, ccna exam, cisco, cisco ios, cisco networking, cisco switches, hints n tips, icnd2, iOS, ios commands, labs, lan, Microsegmentation, networking, study, switch, switches | Permalink
Posted by Josh Gahan
August 26, 2013
- VTP server mode
- No VTP domain name
- VLAN 1 and VLAN’s 1002-1005 are automatically configured (cannot be deleted)
- All access interfaces are assigned to VLAN 1 (an implied switchport access vlan 1 command)
Leave a Comment » | IOS Commands, Networking, Protocols, Switches, VLANs, VTP | Tagged: 4094 vlans, access port, ccna defaults, ccna exam, ccna study, cisco defaults, cisco ios, default vlan, icnd2, iOS, sccess switch, switches, trunking, virtual lan, vlan, vlan 1002, vlan 1003, vlan 1004, vlan 1005, VLAN Trunking Protocol, vlan1, vlans, vtp domain name, vtp server mode | Permalink
Posted by Josh Gahan
June 5, 2013
Types Of Memory In A Switch
| -RAM-
–Working Memory
-Running Config |
-FLASH-
-CISCO IOS Software |
-ROM-
-Bootstrap programme |
-NVRAM-
Startup Config |
Two Main CISCO IOS Files
| Configuration File name |
Purpose |
Where is it stored ? |
| Startup-config |
Stores the initial config used anytime the switch reloads CISCO IOS |
NVRAM |
| Running-Config |
Stores the currently used configuration commands. This file changes dynamically when someone enters commands in configuration mode. |
RAM |
Leave a Comment » | Networking, Switches | Tagged: bootstrap, ccent, ccent study, ccna, ccna exam, cisco ios, flash, icnd1, icnd2, iOS, nvram, ram, rom, running-config, startup-config | Permalink
Posted by Josh Gahan
May 31, 2013
A quick run through the CDP commands to help you map a network, HD is available for this video guys.
[youtube=http://youtu.be/nzGconvPllo]
Leave a Comment » | Networking, Protocols, Videos | Tagged: ccent, ccna, cdp, cisco, cisco discovery protocol, cisco ios, cisco networking, cli, icnd1, iOS, networking, nvram, router, show cdp, switch | Permalink
Posted by Josh Gahan
April 28, 2013
Switches examine the source MAC address of the received frame, switches can take a few possible options if it discovers that the incoming MAC address on that port is NOT SECURE.
- shutdown (the switch shuts down the port and sends a log message and drops the frame/s , also the interface status will read err-disabled you have to run a no shutdown to open the port again) ON BY DEFAULT
- restrict (drops the frames and transmits a log message but does not shutdown the port)
- protect (only drops the frames)
When configuring Port security and the source MAC address is unknown switchport port-security mac-address sticky can be used and the switch will use the first mac address learned as the Secure MAC address
Leave a Comment » | Networking, Security, Switches | Tagged: advice, ccent, ccent exam, ccna, ccna exam, cent, cisco, cisco hardware, cisco ios, cisco switches, cisco switching, did you know, err-disabled, hints n tips, information technology, iOS, ios commands, it, it security, mac, mac address, networking, packet, port security, protocol, router, security, switches, TCP, transmission control protocol, UDP | Permalink
Posted by Josh Gahan
April 28, 2013
Cisco Switch Defaults
- All cisco switch ports are open by (DEFAULT)
- Attempting to trunk (DEFAULT)
- Remember all ports are in VLAN1
Best practice habits should include
- Close Unused ports (shutdown command)
- Stop the port from trunking with (switchport mode access command)
- Place all unused Ports into an unused VLAN
Remember the switches should be locked away in a secure room and or a cabinet
Leave a Comment » | Networking, Security, Switches | Tagged: ccent, ccna, ccna exam, cent exam, cisco, cisco ios, cisco switches, information technology, iOS, ios commands, it networking, networking, security, study, switches | Permalink
Posted by Josh Gahan
April 24, 2013
[youtube http://www.youtube.com/watch?v=rtiDfh-CILs&w=560&h=315]
Leave a Comment » | Networking, Videos | Tagged: advice, ccent, ccent exam, ccna, ccna exam, cisco switches, did you know, GNS3, hints n tips, iOS, ios commands, labs, networking, Q&A, router, study | Permalink
Posted by Josh Gahan
April 23, 2013
I have just linked to a video i created on Youtube, it explores the routing table and also shows you how to change from prefix notation to dotted decimal. If you like i will continue to make more. Enjoy!
[youtube http://www.youtube.com/watch?v=pFilJ_Kvo3E&w=420&h=315]
Leave a Comment » | Networking, Videos | Tagged: ccent, ccna, ccna exam, cisco, dotted decimal, iOS, ios commands, prefix, routing, routing table, simulator, subnets, subnettting, video | Permalink
Posted by Josh Gahan
December 10, 2012
Serial Link
Setting the Clock Rate (CLOCK RATE INTERFACE COMMAND)
Router#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#int serial 1/0
Router(config-if)#clock rate ? (Can be either clockrate or clock rate depending on model)
With the exception of the following standard values not subject to rounding,
1200 2400 4800 9600 14400 19200 28800 38400
56000 64000 128000 2015232
accepted clockrates will be bestfitted (rounded) to the nearest value
supportable by the hardware.
<246-8064000> DCE clock rate (bits per second)
Router(config-if)#clock rate 56000
Router(config-if)#^Z
Remember the DCE Provides the clock rate to the DTE and without this, your line protocol will remain down
Leave a Comment » | IOS Commands, Networking | Tagged: advice, ccent, ccent exam, ccna, ccna exam, cisco, clock rate, clockrate, command, dce dte/dce, did you know, dte, frame relay, GNS3, hints n tips, iOS, ios commands, networking, Q&A, question, router, serial, serial link, study, wan | Permalink
Posted by Josh Gahan