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.
Are IP NAT Traversal and VPN Passthrough the same thing?
What are the top 10 VPN clients in use today?
Can I use CAT5e instead of plain CAT5? Are they interchangeable?
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Access Point coverage maps
How much do the CCIE exams cost?1
Learning Guide: Voice over IP basics
This guide contains all the VoIP basics and essentials you will need when implementing an IP telephony network.Continue Reading
OSPF configuration
Nuances of OSPF configuration could impact your network more than you expect.Continue Reading
Using passive-interface to prevent DoS
How to use the passive-interface command to prevent Denial of Service attacks.Continue Reading
I have a Cisco router and I want to monitor my bandwidth. Do you know of any software that gives you
IP storage 101 for the network admin
With the advent of IP storage, the time has come for network administrators to get up to speed on storage.Continue Reading
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Are there are any VPN clients for Mac OS X that support L2TP?
What is the difference between an IPsec tunnel and a normal tunnel, and what is the bandwidth of eac
VoIP congestion management - basic queuing methods
A look at some of the basic queuing methods to prevent network congestion.Continue Reading
Layer 3 MPLS VPNs
A look at some of the details of Layer 3 MPLS VPNs.Continue Reading
Diagrams - samples
Some samples of the Visio diagrams described in previous tips.Continue Reading
How do I control Internet bandwidth per IP on my LAN?
802.5 Ethernet vs. 802.3 Token Ring
What layer of the OSI model does a hub operate at?
Tips on working with VLSM
Variable Length Subnet Masks (VLSM) can require some serious number crunching but there are many ways to help make the process simpler.Continue Reading
How can I see who is using the most of our Internet bandwidth over our LAN?
What is 'layered architecture' in computer networks?
View these links to get an understanding of what layered architecture is in computer networks.Continue Reading
What are the characteristic of HDLC protocol?
How long is a bit?
Is it possible to determine the NIC speed of a remote workstation on my LAN?
Router Expert: Cisco asynchronous serial support
Cisco IOS-based routers support three asynchronous serial interface types: Console, Auxiliary, and asynchronous port modules. This tip compares them.Continue Reading
Ethernet throughput
Is there a way to stop the Microsoft DHCP server from handing out an IP address to unauthorized mach
Could you compare SONET versus Frame Relay with ATM networks.
Keep networks healthy with patch management
A vigorous patch management process, supported by powerful, centralized tools can go a long way toward ensuring the health of a network far into the future.Continue Reading
Can features such as VPN pass-through on routers be abused to dump traffic onto a NAT'd LAN?
MPLS Versus IPSEC VPNs: Which one is right for you
An examination of the similarities and differences between IPSEC and MPLS and some insight as to when one should be used over the other.Continue Reading
When one reads about the "edge" or the "border" of a network, what does it mean?
Tracking to ensure failover
Using SAAs tracking feature to ensure that your routers use the best traffic route.Continue Reading
Network diagrams and documentation: Part 1
Network diagrams and documentation are the topics of this tip on keeping your network organized.Continue Reading
If I connect two 5-port switches, do I end up with the same throughput as an 8-port switch?
Network management is critical to systems integration
One of the most critical, yet often overlooked, components to effective systems integration is network management.Continue Reading
Integrating RADIUS with an MSSP's remote access VPN
Network security expert Lisa Phifer addresses the integration of RADIUS with an MSSP's remote access VPN.Continue Reading
How do the clients in a WLAN communicate with the AP (Access Point) based on IP in the Network Layer
How do secondary networks work?
Combining VPN and WLAN technologies
Can you explain why certain wireless routers will not work with VPN connections?
Are packets sent inside frames, or are frames inside packets?
Should I use a hardware or software VPN?
I have read up on the software (Windows 2000) and also the hardware (Symantec Firewall/VPN) and I am scheduled to set one up in January. I think I am going with the hardware VPN. If you have any info, tips, suggestions they'd be welcome.Continue Reading
Client-side security considerations for SSL VPNs
Clientless SSL VPNs may be attractive for their lack of software, but they still require client-side security measures.Continue Reading
Optimizing Internet bandwidth with link load balancing
Learn how link load balancing can provide an efficient, cost-effective, and easy-to-use solution to maximize utilization of Internet access.Continue Reading
Network security, quiz: Lessons 1 - 4
Did you find our Administrator Academy lessons on network security useful? Take this quiz to see what you learned.Continue Reading
What you need from your routers in today's network environment
As we push toward IP network environments, multi-functional routers offer many benefits.Continue Reading
Are networking jobs being outsourced as much as developer jobs?
MHSRP - Multi-group Hot Standby Router Protocol
How to use MHSRP to easily distribute your T-1 traffic over two routers.Continue Reading
10 steps to secure instant messaging
If you have or are considering deploying IM system in your corporate communication infrastructure, this tip offers you guidelines for keeping it secure.Continue Reading
WLAN security: Beyond the VPN
Wired networks have used virtual private networks (VPNs) to secure transactions across this edge, but this approach has its limitations.Continue Reading
Advanced packet filtering
In this article, Laura Chappell shows you the steps required to build an advanced filter using the Sniffer Pro.Continue Reading
What is EAP-FAST?
What happens when wireless stations roam?
Restricting access between two LANs
How do I evaluate the performance of a LAN setup?
Do simultaneous uploads slow down my downloads?
What are the top five companies that are providing enterprise level WLAN products and solutions?
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
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
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?
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 -