Problem solve
Get help with specific problems with your technologies, process and projects.
Problem solve
Get help with specific problems with your technologies, process and projects.
Bottom up approach to network troubleshooting
Last week we covered the top down approach to troubleshooting, this week we look at bottom up network troubleshooting. Continue Reading
Modulation types
What is the difference between internal and external commands?
In this expert answer, learn how to tell internal and external commands apart. Continue Reading
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What does the 'no atm ilmi-keepalive' command do?
What does the "no atm ilmi-keepalive" command do? Continue Reading
How can I configure an uplink from a router to a switch using two VLANs?
How do I write test cases based on Proxy functionality?
The network's down - Top down approach to troubleshooting
This article explains some of the methodologies used in using the top down approach to network troubleshooting.Continue Reading
Basic packet filtering
Laura Chappell discusses the basics of address filters, protocol filters, and data set filters.Continue Reading
Logical Fault Isolation in six steps
A handy list of steps to solving complex networking problems, complete with an easy to remember acronym.Continue Reading
Preventing viruses and worms
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Three essential ingredients for network integrity
Yankee Group analyst Eric Ogren says it's time to shift our thinking about network security from a defensive, attack-centric approach to a proactive, access-centric approach.Continue Reading
Network auto discovery and diagramming
Microsoft's Visio, a diagramming package, is also available in an Enterprise edition that can do discovery as well.Continue Reading
Measuring network throughput in Unix
Some useful utilities for measuring throughput in Unix.Continue Reading
Looking for trouble: ICMP and IP statistics to watch
EtherPeek's Summary Statistics window lets you easily identify network scans (ping, ARP, TCP, and UDP) and OS fingerprinting on the network.Continue Reading
I'm unable to share files over my wireless network. Where should I begin troubleshooting?
What is the VPN Box and how does it relate to the VPN module?
Our VPN expert answers the questions: What is the VPN Box? What is the relation between VPN Box and VPN module on the router?Continue Reading
Is it possible to establish a VPN connection programmatically?
What is the bandwidth utilized on Internet VPN?
Computer Networks: A Systems Approach, Chapter 1
This chapter identifies the key metrics that are used to evaluate the performance of computer networks.Continue Reading
Getting DNS statistics and information
A command line tool that can help you diagnose DNS issues.Continue Reading
Cisco IOS disaster recovery
This article explains how to recover from a bad IOS upgrade.Continue Reading
Snapfiles
A look at some of the downloadable tools available at Snapfiles.Continue Reading
How do I stop broadcasts on the wireless segment of my network? Could I use a router?
How do I stop broadcasts on the wireless segment of my network? Could I use a router?Continue Reading
How do I obtain the dB gain/loss of cables and antennas?
What is the purpose of an ACL?
Understanding the wireless landscape, part 1
In her latest tip, mobile wireless expert Lisa Phifer breaks down wireless technologies by category according to distance and intended use.Continue Reading
Understanding the wireless landscape, part 2
Part 2 of Lisa Phifer's comparison of wireless technologies.Continue Reading
I have just completed my CCNA certification and I wanted to continue further with this process. So I
Outsourcing license management
Consider outsourcing license management as a way to offload one of the more tedious and time consuming network manager responsibilities.Continue Reading
Network Analysis, Architecture and Design: Chapter 1
Chapter 1 introduces the analysis, architecture, and design processes.Continue Reading
What would be the best, or easiest, way of increasing the number of IP addresses we have at our disp
What is the difference between physical design and logical design of a network?
Pros and cons of wireless Ethernet bridge and PRI ISDN service
What are the advantages and disadvantages of wireless Ethernet bridge as well as PRI ISDN service. What should be the better choice for me to use?Continue Reading
Is there a simple way to block IRC and IM?
How can I share a dedicated lease line from one building to another?
IPsec tunnel within an IPsec tunnel
Bandwidth management solutions
Some ways to manage your bandwidth, whether you have money to spend or not.Continue Reading
Is there any way to find number of systems connected to a particular system in a network?
Network Security: The Complete Reference
Chapter 10 - Network Device SecurityContinue Reading
Who exactly gives out IP addresses to companies?
Can I connect my PC to my cable modem wirelessly without using a router and just an access point?
Could you help me with my firewall requirement analysis?
How does a multiprotocol router work when it comes to communicating between two different networks -
Error message - invalid domain name
Why would a wireless access point have two antennas?
What is the difference between active hub and passive hub?
A hub can be classified as active, passive or smart; understand the differences to help you decide what you need in your network.Continue Reading
What is FastPing and what is it used for?
What is the difference between IP telephony and voice over IP (VoIP)?
No more polluted caches!
Why it happens, and how to stop it.Continue Reading
Manage your authorizations
How to use the MMC snap-in for managing authorizations.Continue Reading
Do we have standards for switches?
IM policy management
Instant messaging security has often been neglected in most organizations, writing it into a security policy is usually a good start.Continue Reading
Is there any way that I can block MAC addresses using DHCP server or other third part software?
I'm having issue with installing a router/WAP behind another router (which goes to my ISP). Can you
What does the twist in the Cat5 cable do?
What methods can I use to protect our network from broadcast and multicast storms?
What is a smart hub as opposed to one that is not (dumb hub)?
Can I create a network with two computers using a regular modem?
Is it possible to connect a switch to a hub with a distance of 100 meters or more?
Which is better - a firewall appliance or a dedicated machine running firewall software?
Router Expert: Configuring CBAC - Policy configuration and CBAC implementation
In this tip we focus on policy configuration and CBAC implementation on IOS FFS capable routers.Continue Reading
The importance of securing the backup and restore networks
The importance of securing the backup and restore networksContinue Reading
What is the best solution for access control on a wireless network?
Can I use this D-Link Wireless Broadband router as a hub to connect my PC's in workgroup?
What are some examples of Web filtering software products out there?
How does a headend work?
How does the sender of a data packet know the IP address of the receiver? Part 1
How does the sender of a data packet know the IP address of the receiver? Part 2
What is open and close protocol? What is the difference?
Why is "Access denied" when I try to configure trust relationships between two domain servers?
What factors influence the choice of category 5 UTP cable and 100BaseT architecture for the office?
How many different kinds of LAN cards are there?
I need to connect a printer through the print server to a serial port on a Digiboard in order to ena
Backup basics: Three backup plans
Backup basics: Three backup plansContinue Reading
Which transmission media are the most secure? Least secure?
Virtual LANs -- Basics
A decade ago, a simple switch was something that only large companies with big budgets could afford, while the rest with tight budgets were left with hubs as their only affordable solution to interconnect their local networks. One of the most ...Continue Reading
What are the main advantages of ATM technology, and how does EoATM work?
How can I share my cable modem Internet connection through my wireless router?
It takes a long time (3-5 minutes) for my computer to recognize the wireless connection (or router).
Designing a backup architecture that actually works
When it comes to effectily backup design, there are four basic options to choose from: LAN-based, LAN-free, client-free and server-free backup. W. Curtis Preston details each.Continue Reading
Sometimes I get a message, 'port already open." What does it mean?
What does it mean to 'split your network?'
What is the difference between flow control and congestion control?
Calculate the cost of downtime (ROI calculator)
Calculate the value of your network time and define how much money you can save by fixing network problems quickly and efficiently using a network analyzer.Continue Reading
Is there job potential with just CCNA or do I need more certs?
What certification would you recommend for mainframe security experts?
How do I delete an old user account on a Cisco 1700 series router?
What causes unexpected termination of Remote Procedure Call (RPC)?
Sharing a single Internet connection from multiple satellite offices
What are the benefits and drawbacks of Logical Network Design?
Why does the OSI model have 7 layers - no more no less?
Analyzing your network: Statistical monitoring vs. real-time performance
Here's a look at some pros and cons of using prior statistics to make management decisions for future planning and we'll take a look at some alternatives.Continue Reading
What is required to implement SSL with encryption for TN3270 session on CS for OS/390 V2R10?
What is router Initialization Process?
Troubleshooting slow FTP speed over Cisco switches
Can csma/cd technology be used in ring topology?
What is split-horizon and its significance in routing?
Where could I find info on active probing technology to monitor network environments?
What is the difference between "Hz" and "bps"?
Is possible to use a cellular phone to access client server application or receive information from