How to Configure CISCO Router Password?

Passwords are used to restrict access to a CISCO router. Passwords can be given to the virtual terminal lines and the console line. Moreover, password can be set privileged EXEC mode. This page will provide the information to set up CISCO router password to virtual terminal lines, console lines and privileged mode. Even more, you will learn how to encrypt the password also.

Why console password is required?

Console password is useful on a network on which multiple people have to access to the router. The persons who are not authorized, can't access the router. Thus it prevents unauthorized person from accessing the router.

Configuring console password of a CISCO routers:

1. Enter global configuration mode of the CISCO router.
2. Put the command line console 0 to the router.
3. Provide the password by using password command. For example, if you want to put password "cisco" then the command will be password cisco.
4. At last, put the command login.

Commands for configuring console password

Router>enable

Router#config t

Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)#line console 0

Router(config-line)#password cisco

Router(config-line)#login

Router(config-line)#

Why virtual terminal password is required?

Virtual terminal password refers to telnet password. Through telnet, you can access the router and can change anything. So, it's really important to protect the use of telnet by giving a strong password.

Configuring virtual terminal password of a CISCO router:

Different hardware has different no of vty lines defined. Cisco has the range 0 to 4 vty lines. It means it has 5 vty lines. You can set the password of vty lines by the following steps:

1. Enter global configuration mode of the CISCO router.
2. Put the command line vty 0 4 to the router.
3. Provide the password by using password command. For example, if you want to put password "cisco" then the command will be password cisco.
4. At last, put the command login.

Commands for configuring virtual terminal password

Router>enable

Router#configure terminal

Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)#line vty 0 4

Router(config-line)#password cisco

Router(config-line)#login

Router(config-line)#

Why enable password is required?

Enable password is required to restrict the access of privileged EXEC mode.

Configuring enable password of a CISCO router:

From the global configuration mode, use the command enable password to restrict access to privileged EXEC mode. However, this password is visible in the routers configuration file. To encrypt the password, enable secret command is required. By using enable secret command the password is encrypted and can't be readable to a human.

Commands for configuring enable password

Enable password:

Router>enable

Router#config

Router#configure terminal

Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)#enable password cisco

Router(config)#

Perform password encryption:

Router>enable

Router#config

Router#configure terminal

Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)#enable secret cisco

Router(config)#

How to encrypt all the CISCO router password?

By default all the passwords of a CISCO router is readable in clear text in the configuration file. This is a great security threat if someone read it and configure or change the router configuration. So, to protect form display the password, service password-encryption command is used to encrypt the passwords. Service password-encryption is a global command and encrypt the passwords:

• enable password
• console password
• vty password
• aux password

By following the above steps you can easily configure CISCO router passwords.

More Cisco ROUTER INFO:
cisco 1900 router modules, cisco router 1900 modules, Cisco 1900 accessories power

EIGRP Neighborship Troubleshooting

As was shown in the OSPF neighborship troubleshooting article earlier, there are a number of things that need to be configured correctly for everything to end up working as planned. This article takes a look at these requirements from the perspective of Enhanced Interior Gateway Routing Protocol (EIGRP) and shows the different commands that can be used to ensure proper EIGRP neighborship configuration and communications between devices.

EIGRP Neighborship Requirements

From the perspective of EIGRP, there are a couple of things that must match for a EIGRP neighborship to establish; keep in mind that these are different from other routing protocols (like OSPF ), these include:

1. The devices must be in the same autonomous system (AS)
2. The devices must have the same authentication configuration
3. The devices must have the same k-values

EIGRP Neighborship Configuration Verification and Troubleshooting

Starting from the top of the list, the interfaces connecting devices must be on the same autonomous system. To display the various commands and what to look for, Figure 1 shows a simple lab has been setup with two devices that are connected together via an Ethernet connection.

Figure 1 - Simple Lab

The first thing that is going to be checked by the EIGRP device is whether the remote device is in the same autonomous system. No other processing will occur on the device until both devices have been configured with the same area. The troubleshooting for this type of problem requires someone with access to the remote device; this is because there is nodebug command that can be used that will show an obvious AS mismatch. The only way to confirm that this is the problem is to verify the configuration of the devices and verify the AS is the same on each. Figure 2 and 3 below show the EIGRP configuration on both R1 and R2; R2 has been configured with the incorrect AS (AS 1).

Figure 2 - Mismatched Autonomous Systems (R1)

Figure 3 - Mismatched Autonomous Systems (R2)

The second entry on the list was that each device must have matching authentication configuration; before any other information is exchanged between the devices they must agree on an authentication type (if any is configured). EIGRP has a number of different errors messages that are given depending on the specific authentication based failure. The message that is shown in Figure 4 is given when a local device that is not configured with EIGRP authentication is attempting to communicate with a remote device that has an existing authentication configuration.

Figure 4 - Local Missing Authentication Configuration (Complete)

The message that is shown in Figure 5 is given when the local device has been partially configured with EIGRP authentication.  In this example, EIGRP authentication has been configured on the connecting interface but the key chain has not yet been configured (no live authentication keys).

Figure 5 - Local Missing Authentication Configuration (No key chain configured)

For the next couple of authentication examples, the local device has already been configured correctly for EIGRP authentication but the remote device has not. The message that is shown in Figure 6 is given when a remote device has not been configured with any authentication configuration.

Figure 6 - Remote Missing Authentication Configuration (Complete)

The message shown in Figure 7 is given when the remote device has EIGRP authentication configured but does not have a configuration that matched with the local configuration (commonly this is a key string mismatch).

Figure 7 - Remote Authentication Configuration Mismatch

The final entry on the list was that the k-values must match between the communicating devices. Typically, the default values are not changed but if they are, each of the neighboring devices must share the same values. The message that is shown in Figure 8 is given if a mismatch is detected between EIGRP devices; no debug command is required for this message to be displayed.

Figure 8 - k-value Mismatch

Summary

A neighborship is the first thing that must be established before any communication will happen between devices. Each of the different routing protocols has their own requirements that must be met before this neighborship will establish. This article takes a look at the elements that must match for EIGRP neighborships to establish and what commands to use to troubleshoot which misconfiguration potentially exists. Hopefully, the information in this article, when committed to memory, will help in future EIGRP configuration endeavors.

---http://www.petri.co.il/eigrp-neighborship-troubleshooting.htm

More Related Cisco Networking Tips:

cisco 1900 licenses

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What Router-switch.com Prepared for Its 10th Anniversary?

During the past ten years, from 2002 to 2012, router-switch.com has grown up into a global leading Cisco supplier. Indeed, it has experienced several vital moment. Here let’s share some router-switch.com’s big events:

2002, Router-switch.com was founded.

2003, Router-switch.com has experienced a rapid development.

2004, CCIE technical support team was built.

2005, The sales volume maintains 70% growth per year.

2006, Staff in company increased to 20.

2007, Router-switch.com established its marketing department. It attained its reputation in providing timely information of Cisco for clients and Cisco users.

2008, Router-switch.com adopted necessary advanced management tools to improve its service for clients.

2009, Router-switch.com upgraded warehouses in Hongkong and Mainland China. Its inventory is worth over $5 million.

2010, The sales of Router-switch.com have zoomed to $ 30 million.

2011, Router-switch.com released the new version to update service. It supplies free CCIE support. Social network platforms were opened to communicate with customers and clients well.

2012, New Office of router-switch.com landed in US to offer professional local service.

Nowadays, router-switch.com is becoming the world’s largest Cisco reseller online.  It believes that router-switch.com will bemore professional, more reliable and stronger with your support.

Note:A letter from CEO of router-switch.com to thank its customers and sharetheir progress.

http://www.router-switch.com/10years/milestones-and-letter.html

More about Router-switch.com:

Router-switch.com, also called YejianTechnologies Co., Ltd, is the worldwide leader in delivering new, used, refurbished Cisco hardware, including Cisco routers, Cisco switches, firewall security, Cisco IP Phones VoIP, wireless AP, Cisco modules & cards, memory, and optical cables, SFP, GBIC, XENPK , etc. It carries over $5 million in inventory of Cisco hardware and Cisco equipment that can meet SOHO, small, midsized and large businesses of all sizes. Also Router-Switch.com owns more than 8,000 customers worldwide, not only because of its original Cisco products with reliable quality and competitive price, but also due to professionalservice, huge inventory, flexible payment and shipment. More information about router-switch.com can be found at http://www.router-switch.com/. For ongoing Cisco info, please go to

Blog.router-switch.com---News, tutorials, tips, info & thoughts on Developments in the Cisco, Cisco network, IT, Software & Network Hardware Industry

http://blog.router-switch.com/.

More Related Router-switch.com News:

Router-switch.com Announced Its Newly Redesigned Website

http://blog.router-switch.com/2012/09/router-switch-com-announced-its-newly-redesigned-website/

“Router Switch”, Our New Company Landing in U.S.—Professional Cisco Supply Service is Around You

http://blog.router-switch.com/2012/07/%E2%80%9Crouter-switch%E2%80%9D-our-new-company-landing-in-u-s-professional-cisco-supply-service-is-around-you/

Router-switch.com: A Batch of New Cisco Network Equipment Surprises the Coming Christmas Day

http://blog.router-switch.com/2011/12/router-switch-com-a-batch-of-new-cisco-network-equipment-surprises-the-coming-christmas-day/

Router-Switch.com Uploaded Thousands of New Cisco Products

http://blog.router-switch.com/2011/11/router-switch-com-uploaded-thousands-of-new-cisco-products/

Cisco Switch Port Security---How to Configure Switch Security?

Conventional network security often focuses more on routers and blocking traffic from the outside.cisco switch are internal to the organization and designed to allow ease of connectivity, therefore only limited or no security measures are applied.

The following basic security features can be used to secure your switches and network:
* Physically secure the device
* Use secure passwords
* Enable SSH access
* Enable port security
* Disable http access
* Disable unused ports
* Disable Telnet

Let’s look at how to implement and configure some of the above mentioned switch security features.


1. How to Configure the privileged EXEC password.
Use the enable secret command to set the password. For this activity, set the password to orbit.
SW1#configure terminal
SW1(config)#enable secret orbit
SW1(config)#

2. How to Configure virtual terminal (Telnet) and console passwords and require users to login.
A password should be required to access the console line.  Even the basic user EXEC mode can provide significant information to a malicious user. In addition, the VTY lines must have a password before users can access the switch remotely.
Use the following commands to secure the console and telnet:
SW1(config)#line console 0
SW1(config-line)#password cisco 3750
SW1(config-line)#login
SW1(config-line)#line vty 0 15
SW1(config-line)#password cisco
SW1(config-line)#login
SW1(config-line)#exit
SW1(config)#

3.How to Configure password encryption.
At this stage, the privileged EXEC password is already encrypted. To encrypt the line passwords that you just configured, enter the service password-encryption command in global configuration mode.
SW1(config)#service password-encryption
SW1(config)#

4. How to Configure and test the MOTD banner.
Configure the message-of-the-day (MOTD) using Authorized Access Only as the text. Follow these guidelines:
i. The banner text is case sensitive. Make sure you do not add any spaces before or after the banner text.

ii. Use a delimiting character before and after the banner text to indicate where the text begins and ends. The delimiting character used in the example below is %, but you can use any character that is not used in the banner text.

iii. After you have configured the MOTD, log out of the switch to verify that the banner displays when you log back in.

SW1(config)#banner motd %Authorized Access Only%
SW1(config)#end
SW1#exit

5. How to Configure Port Security
Enter interface configuration mode for FastEthernet 0/11 and enable port security.
Before any other port security commands can be configured on the interface, port security must be enabled.
SW1(config-if)#interface fa0/11
SW1(config-if)#switchport port-security
* Notice that you do not have to exit back to global configuration mode before entering interface configuration mode for fa0/11.

6. How to configure the maximum number of MAC addresses.
To configure the port to learn only one MAC address, set the maximum to 1:
SW1(config-if)#switchport port-security maximum 1

7. How to configure the port to add the MAC address to the running configuration.
The MAC address learned on the port can be added to (“stuck” to) the running configuration for that port.
SW1(config-if)#switchport port-security mac-address sticky

8. How to Configure the port to automatically shut down if port security is violated.
If you do not configure the following command, catalyst 3750 SW1 only logs the violation in the port security statistics but does not shut down the port.
SW1(config-if)#switchport port-security violation shutdown
Use the show-mac-address- table command to confirm that SW1 has learned the MAC address for the intended devices, in this case PC1.
SW1#show mac-address-table
Mac Address Table
-------------------------------------------
Vlan Mac Address Type Ports
---- ----------- -------- -----
20 0060.5c4b.cd22 STATIC Fa0/11

You can use the show port-security interface fa0/11 command to also verify a security violation with the command.
SW1#show port-security interface fa0/11

Port Security : Enabled
Port Status : Secure-shutdown
Violation Mode : Shutdown
Aging Time : 0 mins
Aging Type : Absolute
SecureStatic Address Aging : Disabled
Maximum MAC Addresses : 1
Total MAC Addresses : 1
Configured MAC Addresses : 1
Sticky MAC Addresses : 0
Last Source Address:Vlan : 00E0.F7B0.086E:20
Security Violation Count : 1

9. How to Secure Unused Ports
Disabling unused switch ports a simple method many network administrators use to help secure their network from unauthorized access. 3750 series switch Disabling an unused port stops traffic from flowing through the port(s)
Step 1: Disable interface Fa0/10 on SW1.
Enter interface configuration mode for FastEthernet 0/17 and shut down the port.
SW1(config)#interface fa0/10
SW1(config-if)#shutdown

Step 2: Disable interfaces Fa0/1 to Fa0/24 on SW1
SW1(config)#interface range fa0/1-24
SW1(config-if)#shutdown

Cisco Switches: Basic A & Q to Know Details of Cisco Catalyst Switches

Most business networks today use switches to connect computers, printers and servers within a building or campus. A network catalyst switch serves as a controller, enabling networked devices to talk to each other efficiently. Through information sharing and resource allocation, switches save businesses money and increase employee productivity.There are many basic questions got from Cisco switch users, which help you solve some problems while using network switches. Let’s check them…

Basic A & Q to Know Details of cisco catalyst switch

Q: I have a cisco 2950c-24 switch with two fiber ports but say 100base-fx. I tried connecting a fiber connection to a GBIC switch that has 10 GBIC ports but they will not talk to each other. I have in the same rack a 2948 switch with two fiber ports but these ports say 1000base-sx and this switch does talk with the 3550 GBIC switch. Is there any configuration I can do to make them talk? Thanks

A:The fiber ports on the 2950C are 100 Mbs only while the GBICs on the 3550 are 1000 Mbs and you can't go back in speed both ports are forced to their stated speed and no configuration can change that. So you need to get a 2950 - 24 with 2 GBIC ports so you can link them up. If in doubt get LX GBICs as they will talk over most types of fiber, SM 1310 or MM 850. Remember you can always shoot a SM light down a MM with some loss rather than MM down a SM fiber with total connection loss.

Source(s):http://www.cisco.com/en/US/products/hw/s…

MORE NOTES:There are many types of fiber connectors to include SX, LX, SC, ST, LC....etc.
Each GBIC can only use the connector that it is designed for.
You have described a 2950 with a 100base-fx port. This only means "fiber" as opposed to 100base-tx (Copper). You described the 2948 as having 2 1000base-sx ports (GB Capable SX connector).
There are two options:
1. Determine which type of connector is used on your 2950 and use a fiber patch with that type on the 2950 and SX on the 2948.
2. Connect the fiber patch from the 2950 to a patch panel (usally ST) and from there patch it to an SX patch cable the 2948 (or appropriate connector to the 3550 GBIC).

Q: Is it safe to reset a Cisco Catalyst switch by disconnecting/reconnecting power?I have a Cisco 3560G switch that has one port locked because I failed to use a crossover cable when I tried to add another switch downstream. Can I safely unplug the switch to force the switch to reset? This works for servers and linux boxes, but I do not know about Cisco switches.

A: Yes it is safe, Just ensure that you leave it off for 3 mins.

Q:How to connect two DHCP servers within cisco switch 3550 10 gigabit ports?I have two DHCP servers with different subnet connect to the same cisco switch 3550 with 10 gigabit ports. Port # 2 connect to DHCP server1, Port # 3 connect to DHCP server2 and Port # 3 connect to dhcp client zone. Is it impossible to work out? If yes, please tell me on how to do it!Thanks so much in advance! :-)

A: First off, if someone has sold you a 3550 telling you it is a 10G switch, you have been had.
Beyond that, we need to know a little more about what you are trying to do.
The simple option is something like
intfas 0/1
des DHCP server 1
switch mode acce
switch accevlan 10
no shut

intfas 0/2
des DHCP server 2
switch mode acce
switch accevlan 20
no shut

intfas 0/3
des user to get address from DHCP server 1
switch mode acce
switch accevlan 10
no shut

intfas 0/4
des user to get address from DHCP server 2
switch mode acce
switch accevlan 20
no shut

ip routing

intvlan 10
ipadd<default gateway of the scope of DHCP server 1>
no shut
intvlan 20
ipadd<default gateway of the scope of DHCP server 2>

These last two can be repeated as you wish to allocate users to DHCP servers.
This will allow the users on both VLANs too contact each other.

MORE TIPS: You may need to add
intvlan 10
ipadd<default gateway of the scope of DHCP server 1>
ip helper-address <IP of your DHCP>

if you do not have it on the router.
And a little bit explanation from Cisco doc:
ip helper-address

To enable the forwarding of User Datagram Protocol (UDP) broadcasts, including BOOTP, received on an interface, use the ip helper-address command in interface configuration mode. To disable the forwarding of broadcast packets to specific addresses, use the no form of this command.

ip helper-address [vrf name | global] address [redundancy vrg-name]

Source(s):

http://www.cisco.com/en/US/docs/ios/12_3t/ip_addr/command/reference/ip1_i1gt.html#wp1169356

Q: Does the cisco switch IOS 4506 provide same functionality as Cisco Switch 6509?At this point I have a Cisco 6509 switch as the main router of a network. I'm forced to change it with a 4506. I want to know if the functionality will be the same or would I have any problems?

A:To determine whether any of the differences will affect you, first determine what IOS/CatOS image you were running on the 6509 then do the same for the 4506 and go here:http://tools.cisco.com/ITDIT/CFN/Dispatc…, it is Cisco's feature comparison tool. You can enter all the parameters in and see what features are exclusively available to one platform or the other. If they are features you need, you know it will not work. If you do not need any of them, then you should be OK.

Q: How would a Cisco Switch stop Ping?Look for any statement I should be looking for in the running config of a Cisco 2950 or 3550 switch. Anything that would stop ICMP echo request packets.

A: Ping what? The SVI? Anything? These are strictly Layer 2 switches, you might be able to write an ACL to stop Ping to the SVI on THAT switch, but in general they will not support ACL's to be applied on interfaces because Layer 3 interfaces are not supported on those two models.If you wanted to stop it on an SVI, I think it would need to be an extended ACL, an example might be:
ip access-list extended Block_Ping
deny icmp any anyeq echo
permit ip any any

Q: Can you connect an Avaya phone to cisco switch?Can you connect an Avaya phone to cisco switch?

A: If they are IP phones they may be SIP compatible. If they are SIP compatible, you need to ensure your switch supports SIP and then it can be set up as a SIP Station.You need to work with your Cisco business partner. Either way it may be pricey.If you want to sell the phone that is always an option

Q: How can I configure a 24 port cisco switch with 3 Vlans?I forgot the commands and can't figure this out. I want to configure 3 vlans. F0/0 - 7 as vlan 1, ports 8-15 as vlan 2, and ports 16-24 as vlan 3. I seem to remember "switchport access" but can't remember the rest. Does anyone have detailed commands?

A:Log into the router, switch to enabled mode ('enable'), then configuration mode ('conf t').

To configure an interface, go to interface configation mode ('interface F0/0' or whatever). To set a port to be in a single VLAN, use:
switchport mode access - put the port in access (single VLAN) mode
switchport access vlan X - set the port's VLAN
Replace 'X' with the vlan number, of course.

You can configure more than one interface at a time. Your full sequence should be:
enable
conft
interface range F0/0 - 7
switchport mode access
switchportvlan 1
exit
interface range F0/8 - 15
switchport mode access
switchportvlan 2
exit
interface range F0/16 - 24
switchport mode access
switchportvlan 3
exit
exit

Q: Help needed to upgrade my cisco switch ios?I have connected my switch via console cable, I have set up a tftp server on my PC when I try to update the ios it keeps timing out.

A:First, your computer with the tftp server and the switch need to be connected via the network. When the switch pulls the image, it's not through the console cable, but rather an ethernet port.

Second, your new IOS image needs to be in the correct folder on your local hard drive so the tftp server can reach the file and serve it to clients that ask. This varies greatly by tftp server, so I can't give you clear directions for how to do this.

Third, your switch needs an IP address assigned to a vlan interface. Typically, vlan 1 is used, but more advanced users can use a different one. The configuration usually looks like:

configure terminal
interface vlan 1
ip address w.x.y.z 255.255.255.0
no shut
end

To do a little troubleshooting, try pinging your computer from the switch and then ping the switch from your computer. Due to firewalls, this may or may not work, but it's a good tool.

Lastly, once you are sure that connectivity is in place, you issue the command "copy tftp flash" from the switch. The switch will ask you the IP address of the tftp server, then the filename, and then it will probably ask you if you want to erase the flash. You should usually press "enter" to confirm "yes" to erase the flash, otherwise you'll run out of room in the memory. If you do not receive the question to erase the flash, that means there is a connectivity issue.

Hope this helps.

Source(s):

http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00801347e2.shtml

Q: Is it possible todo load balancing on a cisco 3560 switch?Additional Details: I have a building with three floors. Each floor has a 3560 switch that connects to a 4500 switch in the basement. There is also a second link from the 3560s to the 4500 switch in case one link goes down. So I was wondering if I can use both links and then if one link fails, then all the traffic can be routed using the other link.

A: Yes it is possible, but is highly dependent on your particular configuration. Are you running a L2 or L3 image on the switch? If you are trying to do Layer 2 load balancing, you will require multiple VLAN's - or EtherChannel a couple of links together and make sure your src/dst are changing enough to get some load sharing. Layer 3 you will need multiple egress points of course. Hope this helps - will need more specifics to get less generalized in an answer.
<Update> OK, this is an EtherChannel scenario. Take the two ports and bond them together as an EtherChannel (I am not sure still if you are running L2 or L3 3560's - I will assume L2 as they are more common). You should check CCO (www.cisco.com) for exact configuration for your version of software, but essentially you will turn on channeling between the devices, it will leave both links up, load share them and make them redundant.

Source(s):http://www.cisco.com/en/US/tech/tk389/tk…

Q: What does your PC need in order to console into a Cisco switch?

a. COM port
b. Parallel port
c. Firewire port
d. PS/2 port

A: High end cisco switches usually come with a console cable (blue serial to RJ-45). This goes on the management port of your switch and the other end goes into the serial port of your pc.Then you can use the "Hyperterminal" to make a connection to the switch and configure it from there.Other, lower end, switches somethimes have a function that needs you to press a button on the front of the switch for a few seconds, and one of the ports (random) starts to blink. Then you can connect your pc to this port with a normal ethernet cable. your pc will get an IP address from the switch and you can connect to the switch using the gateway address assigned to the pc. This will be the switches web site.

Q: How do I setup a VLAN on a Cisco switch?

A: By default a Cisco switch is already using a vlan (that is, vlan 1). As mentioned, some Cisco switches (particularly older Catalyst switches which tended to be rehashed models from companies Cisco had recently bought) run CatOS. Newer/better switches run Cisco IOS.
As for how to "set one up", it's kind of hard to answer without knowing what specifically you're trying to do. The answer posted above me will create an SVI for a VLAN, which may or may not be what you want depending on your goal (note that the example doesn't assign the VLAN to a physical switchport, or configure a switchport to be an access port for that VLAN).
So to answer a question with a question, what specifically are you trying to accomplish? Just basic L2 LAN segmentation? Do you want/need to be able to route between these VLANs? Are your switch(s) running IOS or CatOS? What is your network topology?

Q: Configuring an ip on a configured Vlan, cisco switch?I need to configure an ip address which is the gateway for which I need that specific port to go to. How do I configure that gateway on that specific vlan?

A: Cisco switches can confuse you with Vlans. If you've defined a Vlan and assign ports to that Vlan (in Catalyst OS or IOS), no gateway is required. But if you are configuring a Vlan interface with an assigned IP address (such as for managing the switch remotely), then you need to define a gateway.

In the excerpt below, let's say we have
--a layer 2 switch running IOS (such as a Catalyst 2950), which we will admin at 192.168.1.250
--a port connected to a home router that is our default gateway and another port connected to a printer at 192.168.1.100
--the IP address of the home router is 192.168.1.1

!
vlan 2
name Admin
!
interfaceFastEthernet 0/1
description home router LAN connection
switchport mode access
switchport access vlan 2
!
interfaceFastEthernet 0/2
description printer - note the IP address doesn't matter
switchport mode access
switchport access vlan 2
!
interfaceVlan 2
description Remote Admin IP of Cisco switch
ip address 192.168.1.250 255.255.255.0
!
ip default-gateway 192.168.1.1

As a layer 2 switch, it can support multiple Vlans. cisco switch configuration But it does not route between Vlans. You could also define a Vlan 10 with another administrative IP address. But you if you were connected to your home router (connected on Vlan 2) you could not reach any ports on Vlan 10, including an administrative IP you created in 'interface Vlan 10'.

Q: How do I select a Cisco switch?

A:Before you can select a switch you first need to figure out all the requirements, like the amount of ports, the speed of the ports etc. Keep also in mind the IOS version that can be necessary for certain funtionalities. For example QoS only works on C2950 with enterprise IOS.When that is done, you can select the switch based on these requirements.

Q: What is the command to disable trunk negotiation on a cisco switch?

A:If you want a port to always be a trunk or always be an access port, then the commands would be "switchport mode trunk" and "switchport mode access" respectively. Now, if you want to disable DTP (dynamic trunking protocol), to prevent the switch from helping the other side to negotiate if it is a dynamic port, then the command would be "switchportnonegotiate".

Q: How I can install IOS into cisco switch 3560 series?In my cisco switch 3560 series hasn't IOS system and I cann't into priveleged EXEC mode. "enable" function cann't run!

A: The first thing you need to do is recover the password so you can "enable" privileged mode - you need to "break" as the switch is about to load, as per this info here:
http://www.cisco.com/en/US/products/hw/r…
1/ Put the new IOS onto a tftp server (if you don't have one, google for "tftp server free download").
2/ Get the switch onto the same network as your tftp server.
3/ decide if you have enough room in either flash or RAM (depending on your switch) and
copy tftp flash

Source(s):http://www.cisco.com/warp/public/474/ind…
http://www.cisco.com/en/US/products/sw/i…

More Notes About Network Switches

What is a Network Switch: Unmanaged Switches?

An unmanaged switch works right out of the box. It's not designed to be configured, so you don't have to worry about installing or setting it up correctly. Unmanaged switches have less network capacity than managed switches. You'll usually find unmanaged switches in home networking equipment.

What is a Network Switch: Managed Switches?

A managed network switch is configurable, offering greater flexibility and capacity than an unmanaged switch. You can monitor and adjust a managed switch locally or remotely, to give you greater network control.

What is a Network Switch versus a Router?

Switches create a network. Routers connect networks. A router links computers to the Internet, so users can share the connection. A router acts as a dispatcher, choosing the best path for information to travel so it's received quickly.

What is a Network Switch to My Business?

Switches and routers are the building blocks for all business communications, from data to voice and video to wireless access. They can improve profitability by enabling your company to increase productivity, trim business expenses, and improve security and customer service.

How to Config the Cisco 3560 Switch

Network switches play an integral role in computer networks by connecting all the devices on the network, enabling communication. cisco ws c3560x 24p s Switches can be simple or complex, ranging from small, four-port home office devices with limited management interfaces to complex, 48 port-enterprise level devices with dedicated memory, processors and operating systems. When dealing with complex models, network administrators spend hours configuring each individual device to the exacting specifications required by their network. As with any piece of important data, these configurations need to be backed up.
What You Will Need While Saving the Cisco 3560 Switch Config
•    catalyst 3560 g
•    Computer with serial port
•    Rollover cable
•    Terminal emulation software (PuTTY)
How to Save the 3560x 24t s Switch Configuration
Connect to the Switch
1. Plug your computer into the switch with a rollover cable. This cable has a RJ-45 jack on one end and a serial connection on the other. Plug the RJ-45 end into the "CONSOLE" port of the switch, and the serial end into your computer.
2. Download and install a terminal program called PuTTY to connect to the switch (see Resources).
3. Open the terminal emulation software. In PuTTY, select "Serial" in the "Category" box on the left, then select the correct COM port in the "Serial line to connect to" box. Click "Open" to open the command line of the switch. The command line is a text-based interface for the switch. It has a prompt where you can enter commands to change settings and configurations.
Save the Configuration
1. Type "enable" at the command line, then press return on the keyboard to enter into "privileged exec mode." cisco ws c3560x 24t l The switch prompt should change from "Switch>" to "Switch#, then you can enter the next command.
2. Type "copy running-config startup-config" at the command line and press return on the keyboard. This will copy the current switch configuration to the non-volatile memory, which is memory that will retain its data even without power applied to it.
3. Type "show running-config" to display the current configuration.
4. Click and hold at the beginning of the output from the "show running-config" command, then drag down to the bottom of the PuTTY window. This should select all the text on the screen.
5. Right-click and select "Copy" to copy the text.
6. Click on "Start" and "Run," Cisco 3560 then type "notepad.exe" in the dialog box. Click "OK" to bring up the notepad program.
7. Click on "Edit" and "Paste" to put the switch configuration into notepad.
8. Click "File" and "Save" to save the file to your desktop. You now have a backup of your switch configuration that will be around even if your switch goes bad.
Tips & Warnings
The command "copy running-config startup-config" can be shortened to "copy run start."

Cisco Catalyst 3750 Series, How to Change the Password on It?

The Cisco 3750 series switch has contributed greatly to Cisco's success in the networking hardware market. Its features provide efficient and reliable network switching services. You can find a pre-owned 3750 model at a good price, and if you do buy a pre-owned Cisco catalyst 3750 series switch, you may need to change the password before you are able configure it to work on your network. Fortunately, Cisco has provided a built-in procedure that allows you to change the password.

Things You'll Need

Cisco 3750 switch and serial cable

Computer with terminal emulation software

How to Change the Password on a Catalyst 3750 Switch？

1. Connect your computer to the cisco 3750G switch using the blue serial cable that typically comes with it. Connect the 9-pin d-shell connector to your computer's serial port, and connect the RJ-45 connector to the switch's console port.

2. Configure a terminal session to the switch. Power up your computer, open a terminal emulator application, and configure a terminal session with the following settings:

9600 baud

no parity

1 stop bit

8 data bits

Xon/Xoff flow control

Save the configuration with a name that you can recognize later.

3. Hold down the "Mode" button on the left front of the Cisco 3750 switch, and plug in the power cable. Five seconds after the Stat LED goes off, release the "Mode" button. The SYST LED should start to blink amber.

4. At the command prompt, issue the following commands to the switch to prepare it for the reset procedure, and rename the current configuration file:

flash_init

load_helper

dir flash:

renameflash:config.textflash:config.old

5. Boot the 3750 switch by issuing the "boot" command and pressing "Enter." At the "System Configuration Dialog" prompt, answer "n" and press "Enter" twice. This should display the "Switch>" prompt.

6. Issue the "en" command at the prompt, and press "Enter." You should see the prompt change from "Switch>" to "Switch#." Rename the configuration file with the following command:

renameflash:config.oldflash:config.text (press "Enter")

Press "Enter" to accept the destination filename default.

7. Copy the configuration file into the 3750 memory with the following command:

copyflash:config.textsystem:running-config

Press "Enter" when prompted for a destination filename to accept the default.

8. eate new passwords for the cisco 3750x switch with the following commands:

conf t

enable secret spswd (spswd = your new secret password)

enable password enpswd (enpswd = your new enable password)

linevty 0 15

passwordtpswd (tpswd = your new terminal password)

login

line con 0

passwordcpswd (cpswd = your new console password)

write memory

The 3750 will issue a "Building Configuration" message. When you see the [OK] message at the Sw1# prompt, you have completed the password change for the Cisco 3750 switch.