Welcome to www.howtocisco.com, an online resource to assist people who are preparing to be or already are network engineers. This website provides a place to learn and share real Cisco troubleshooting network problems. It contains many valuable articles, cases, tools and examples of how to configure Cisco PIX/ASA, Router, Switch, VLAN, VPN and Wireless.

Beginners may want to check these useful pages first:

·        Configure Cisco Password

·        General Configuration

·        Save/Restore Configuration

·        General Troubleshooting

·        Useful Commands

We have a collection of explanations and suggestions on how to resolve Cisco issues and will continue to add more.

For those network engineers who would like to share their insights, concerns and solutions, they can visit this forum. Besides Cisco, this network forum is also a place to discuss the issues of Windows OS, computer network, Internet access, remote access and wireless.

Cisco VPN client errors: Another VPN client activates and the router limits only connection.

VPN Client Reason Code: This table lists and describes VPN Client reason messages with troubleshooting.

Cisco VPN Reason 429: Unable to resolve server address:  The Cisco VPN client can't establish the VPN connection

Cisco Switch: Unexpected BPDU received. Port has been Disabled: “This feature was first implemented to handle special collision situations in which the switch detected excessive or late collisions on a port. Excessive collisions occur when a frame is dropped because the switch encounters 16 collisions in a row”.

Cisco Wireless is not stable: The client has 5 Cisco APs in their Cisco Wireless LAN Controller. The wireless keeps dropping and no stable

NAP with Cisco Routers: I have some users, which are connected to my network via VPN. VPN terminated on Cisco router. Users use PPTP VPN to connect to the office network. I want to use NAP for this clients. Does any one tried this?

W2k8 NPS as a RADIUS server for a Cisco router: I currently have W2k3 IAS configured as a RADIUS server for our VPN clients connecting to a Cisco 2811 router.

Find out which device is using public IP address: the client has over 30 public IP addresses. They can ping all IP addresses, but they don't think they use all of them. They would like to find out which devices are using them.

Enterprise Wireless keeps popup for credentials: The client follow this "How to set up a Cisco Enterprise Wireless Using NPS in Microsoft Active Directory"

Cisco Enterprise Wireless doesn't work: but can't make it work. The wireless keeps popup for credentials. The problem is he doesn't know  this Cisco AP configuration issue or IAS issue.

How to set up a Cisco Enterprise Wireless Using NPS in Microsoft Active Directory: Configure Cisco 1242 AP by following this artcle: How to configure a new Cisco 1242 wireless AP

The example of Initial configuration on Cisco PIX using ASDM: The Adaptive Security Device Manager (ASDM) is web-based design connect to and manage a PIX/ASA using a web browser.

The example of Initial configuration on Cisco PIX version 5.1: In our example, the outside IP address of the PIX is 192.167.1.2; inside IP address inside is 10.0.0.2; the outside LAN/WAN IP range 192.168.0.0/24 and inside is 10.0.0.0/8; the admin workstation IP is 10.0.0.10, Exchange server IP is 10 10.0.0..3, telnet client IP is 10.0.0.11.

How to backup/restore HP swicth config using TFTP:  To backup HP ProCurve witch configuration using TFTP, please follow these steps

How to configure a VLAN port in HP ProCourve Switch using Web Utility: Select the port and Mode to Untagged, which is the port that will be used the specified VLAN, port 4 and VLAN 100 in our example.

How to configure VLAN in HP ProCurve Switch: In this example, we will configure port 21 for VLAN 100

Cisco Switch Initial Configuration: Here are the example of configuring Cisco switch 2995

How to configure channel in Cisco AP: Q: All our Cisco 1200 AP are setup to use lease congested Frequency. However, our security want to use clear channel 1 to 6. How do you configure Cisco AP to use channel 9?

Can't connect Cisco 2955 to 3560G switches: The client wants to configure Cisco switch 2955 to access one of their 3560G switch. However, it doesn't work and the 2955 can't access the 3560.

Can't establish Cisco VPN with HASH payload can't be verified:  Situation: when trying to establish the VPN, the user receives this error: Sev=Warning/3 IKE/0xE3000056. The received HASH payload cannot be verified

How to configure channel in Cisco AP: Q: All our Cisco 1200 AP are setup to use lease congested Frequency. However, our security want to use clear channel 1 to 6. How do you configure Cisco AP to use channel 9?

Configure Cisco Switch for Dell NIC Teaming: We created NIC Teaming in Dell PowerEdge R710 server. The two NICs are connecting to the Cisco switch 3560G without any issues. If we unplug one cable, the server still works and connects to the network. Do we need to configure EtherChannel on those two ports.

Cisco: Wireless client can't receive the IP: Situation: The client tries to setup Cisco wireless 1310 bridge. The client can receive the signal but can't logon the domain. Ipconfig shows the client can't receive IP from the DHCP server and the IP is 169.254.x.x.