Problem solve

Problem solve

Get help with specific problems with your technologies, process and projects.

• How can I prevent a DDoS attack program?

  DDoS programs overwhelm networks with a torrent of requests. How can you prevent a DDoS attack, and what are the steps you can take to keep your networking environment secure? Continue Reading

• How IPv6 networks create DNS configuration problems

  DNS data is among the most basic and crucial information required for network connectivity, but configuring DNS recursive servers in IPv6-only networks can pose challenges. Continue Reading

• What's automation's role in network provisioning resources?

  IT is embracing network automation, but complications with integration disrupt the process. Using automation for provisioning resources can improve efficiency, but reduce the need for IT personnel. Continue Reading

• How can you use perfect forward secrecy for mobile security?

  How can companies increase data protection in mobile communications environments and enhance perfect forward secrecy to safeguard user activity? Continue Reading

• IBN: Enablement for a configuration management process?

  How realistic are claims about intent-based networking helping organizations to enhance the network configuration management process? Continue Reading

• Users want hybrid cloud networking to be simple

  As more services move to the cloud and become more mobile, if the network is invisible and performs well, IT pros are doing their jobs in users' eyes.Continue Reading

• How to use traceroute to troubleshoot network problems

  Traceroute is a tool that can provide more insight than you might think. Learn how to use traceroute to troubleshoot network issues.Continue Reading

• How types of noise in data communication systems affect the network

  Learn about the different types of noise in data communication -- including thermal, intermodulation, cross-talk, impulse and shot noise -- and how they can affect your network.Continue Reading

• Networked cloud emerges to meet evolving infrastructure needs

  Some enterprise network managers are beginning to move networking out to the cloud, as they sort out how to best meet their organizations' evolving infrastructure needs.Continue Reading

• IP subnetting: How to calculate subnet masks

  Check out IP subnetting shortcuts on how to do subnet mask calculations and break down IP address classes to route traffic within your network.Continue Reading

• Comparing cable types: Fiber vs. copper twisted pair

  What's the difference in fiber vs. copper cables? Key differences include cost, speed and more when it comes to fiber optic and copper twisted-pair cabling options.Continue Reading

• What is the difference between bit rate and baud rate?

  Learn how to understand the difference between bit rate and baud rate in this expert answer.Continue Reading

• How can my company reap the advantages of SDN if its culture is risk-averse?

  SDN expert Will Murrell discusses how the advantages of SDN will speak to cautious companies only when network engineers can make a case for SDN's lower cost and high functionality.Continue Reading

• How to troubleshoot iPhone and iPad connection problems

  As iPhone and iPad Wi-Fi clients proliferate in the enterprise, IT must troubleshoot Wi-Fi connection problems. Here's how to solve basic iPhone and iPad connection problems.Continue Reading

• Common network errors and their causes

  Network not behaving? Learn how to identify the most common network errors -- like discards and collisions -- and how to implement solutions to get your network humming again.Continue Reading

• How to troubleshoot Android Wi-Fi connection problems

  Android smartphone and tablet users now abound in the enterprise, making Android Wi-Fi connection troubleshooting a key element of enterprise wireless network connection management.Continue Reading

• How can enterprises manage the cybersecurity skills gap?

  Due to the demand for professionals with backgrounds in both computer science and networking, filling cybersecurity jobs is difficult. Technology will have to play a bigger role.Continue Reading

• What's the best way to handle end-of-sale devices on your network?

  A majority of organizations have end-of-sale and end-of-life devices on their networks. What's the best way to ensure your equipment is up to date?Continue Reading

• OPM hack two months later: What was learned?

  Network security expert Michele Chubirka shares her thoughts about June's OPM hack and what steps IT should take to fend off future attacks.Continue Reading

• Hyper-V networking: The three virtual switches that fuel connectivity

  In this Hyper-V networking primer, learn about the three virtual switches behind Microsoft virtualization connectivity.Continue Reading

• Subnet basics: Must you set up Wi-Fi subnets in a single building?

  Expert Mike Jude discusses the rationale of creating distinct Wi-Fi subnets in a single building.Continue Reading

• Are there alternatives to the OpenFlow protocol?

  Jason Edelman explains OpenFlow protocol alternatives and what's important in determining which southbound protocol will work for you.Continue Reading

• Centralized vs. decentralized SDN architecture: Which works for you?

  Two SDN architecture models -- centralized and decentralized -- have much in common, but key differences center on the use of the OpenFlow protocol.Continue Reading

• How do I disable VPN passthrough? What are the pros and cons to disabling it?

  In this Ask the Expert response, Rainer Enders explains how to disable VPN passthrough and what the benefits and drawbacks are.Continue Reading

• Multiple access point configuration: Distinguish transmitted signals

  Lisa Phifer explains multiple access point configuration when a device tries to differentiate transmitted signals from each point and explains potential issues.Continue Reading

• Using virtual appliances and desktop virtualization

  IT organizations are implementing desktop virtualization and virtual appliances for virtual WAN optimization and virtual application delivery, but there are challenges to overcome along the way.Continue Reading

• Difference between circuit-switching and packet-switching in examples

  What is the difference between a circuit switching and packet switching? Our networking fundamentals expert gives examples of packet switching and circuit switching in this response.Continue Reading

• VLANs versus IP subnets: Why use a VLAN over IP subnetting?

  A virtual local area network (VLAN) is better than IP subnetting because its advantage is security. Learn what a VLAN is and how it differs from creating IP subnets, in this expert response from our networking fundamentals expert.Continue Reading

• Calculating subnets for IP addresses in IPv6

  Understand how subnetting in IPv6 differs from that of IPv4 and what you need to do in order to calculate the subnet of an IP address in IP version 6.Continue Reading

• Network-to-network VPN gateway configuration for Cisco EzVPN

  Learn how to support network-to-network IPsec VPN topologies using a router as the VPN gateway with Cisco EzVPN.Continue Reading

• Troubleshooting remote scripting using Network Monitor 3.0 -- Managing Windows networks using script

  Learn how to use Network Monitor 3.0 for troubleshooting a remote scripting error in this tip originally published on WindowsNetworking.com.Continue Reading

• Optical networks: Core network design best practices

  Core optical network design must take into consideration network requirements specific to the core, including a high degree of aggregation, low reconfigurability, and large geographic scope, while confronting such challenges as router adjacency, ...Continue Reading

• What equipment do I use to connect two LANs in different cities? What are the steps?

  How do you connect two LANS from different cities? VPN expert Sampath Ramaswami notes the steps to be taken, in this Q&A.Continue Reading

• Cisco wireless access point configuration from scratch

  Learn what the Cisco 1242 wireless access point can do for you and how to configure one from scratch. This tip covers basic security settings, enabling the wireless radios, and how to make a successful connection. The 1242AG is a powerful ...Continue Reading

• Cisco WLAN design best practices

  Wireless LAN (WLAN) technology has built-in security features, but a one-size-fits-all approach won't ensure adequate security for your organization. This tip provides best practices for designing your security architecture, including user community...Continue Reading

• What is the relationship between network cable frequency and its bandwidth?

  Learn about the relationship between the network cable's frequency and its bandwidth capacity, the frequency formula and its physics in this expert response by Carrie Higbie.Continue Reading

• MPLS load sharing and high availability, Part 2: IP routing

  MPLS has become a trusted transport option for convergent networks that require guaranteed levels of service, but successful implementation can require increased levels of redundancy to support failover. Robbie Harrell discusses how to enable high ...Continue Reading

• LAN administration guide

  LAN administration is an arduous task and your responsibilities often involve many different aspects and may include many tasks. This guide will help you with each step and task.Continue Reading

• Slow response times from client/server PC's running IFS applications

  How do you find out the culprit of a network delays when you see little bandwidth being used? Read this Q&A to see what our network administrating expert, Lindi Horton, has to say.Continue Reading

• Half duplex vs. full duplex Ethernet 10BASE-T topologies

  Ever wonder why half duplex Ethernet 10BASE-T topologies have a slower data transmission rate than full duplex Ethernet 10BASE-Ttopologies? Find out in this expert response by Lindi Horton.Continue Reading

• What are the fundamental principles of CDMA?

  In this Q&A, our expert, Lindi Horton gives us an explanation of what CDMA is and what some of its fundamental principles are.Continue Reading

• Intrusion detection vs. intrusion prevention

  Our expert, Puneet Mehta, tells us what the key difference is between intrusion detection and intrusion prevention, in this expert response.Continue Reading

• What download speed will I get with a bandwidth of 1 MBPS?

  Wondering what kind of download speed you can get with a bandwidth of 1 MBPS? Our expert, Lindi Horton can give you the lowdown on the download.Continue Reading

• IP addressing and subnetting: Calculate a subnet mask using the subnet's formula

  IP addressing and subnetting are an important part of networks. Learn how the subnet's formula works and why it's important to know how to calculate the subnet mask "longhand."Continue Reading

• System engineer vs. network administrator

  Our Cisco certifications expert, David Minutella, answers what the responsibilities of a system engineer and network administrator are and what makes the two jobs different.Continue Reading

• How IPsec provides secure communications

  IPsec provides secure site-to-site VPNs, remote access and host-to-host communication. In this tip, we peek inside the tunnel and examine how IPsec works.Continue Reading

• VPN client alternatives: Layer 2 Tunneling Protocol (L2TP) over IPsec

  This month, Lisa Phifer discusses a robust VPN client alternative: Layer 2 Tunneling Protocol (L2TP) over IPsec.Continue Reading

• Network test plan: Checklist for architecture changes

  For every change you make to your network architecture, you should have a test plan and a backout plan. In this tip, learn how to build a test plan and review a sample checklist of things to include.Continue Reading

• How SSL and TLS secure network transactions

  SSL and TLS are protocols that were developed primarily to protect Web transactions, but they can be used to protect any type of network traffic that utilizes TCP at the transport layer, including the popular SSL VPN. In this tip, learn how SSL and ...Continue Reading

• Router Expert: Building a WLAN proxy server, DHCP services: Part 1

  Router expert Michael Martin discusses DHCP implementation options and provides sample configurations to support various SSID network models in this continuation of his series on building a WLAN proxy server.Continue Reading

• The most commonly used network operating system

  In this Q&A, Lindi Horton answers the question "What network operating system is more currently and commonly used?"Continue Reading

• OSI: Securing the stack, Layer 2 -- Understanding the role of ARP

  Security expert Michael Gregg continues his layer-by-layer discussion of OSI model network security with this tip on the vulnerabilities present in Layer 2, the Data Link Layer, and specifically addresses the Address Resolution Protocol.Continue Reading

• How round-trip time and limiting data rate impact network performance

  This tip reviews how network parameters such as round-trip time and limiting data rate affect network performance.Continue Reading

• OSI: Securing the stack, Layer 1 -- Physical security threats

  Security expert Michael Gregg kicks off his layer-by-layer discussion of OSI model network security with this tip on securing Layer 1 against physical security threats.Continue Reading

• Duplex mismatch

  What is duplex, and what is the difference between half and full duplex? What is a duplex mismatch? How can autonegotiation help or hurt your network? How can you resolve duplex conflicts? In this tip, David Davis helps networking engineers and ...Continue Reading

• IPSec and NAT incompatibility

  Learn why Authentication Header (AH) doesn't work with Network Address Translation (NAT) or Port Address Translation (PAT) and that Encapsulating Security Payload (ESP) is also incompatible with PAT.Continue Reading

• Wireless LAN setup for hotels

  Phifer discusses the requirements for WLAN setups in hotels.Continue Reading

• VPNs for disaster recovery: IPsec vs. SSL

  Using a VPN as a failover mechanism when a primary communications link may be unavailable due to a disaster can be a smart move -- as well as an easy one to implement. In this tip, learn about the pros and cons of IPsec and SSL VPN options for ...Continue Reading

• Troubleshooting wireless networks: A systematic approach

  Troubleshooting wireless networks can take up a lot of time for network operations staff with a wireless LAN (WLAN) environment. Wireless guru Lisa Phifer discusses the tools and processes involved and breaks down how to approach and resolve ...Continue Reading

• DNS for a wireless network: Router Expert

  DNS services are essential for building a secure wireless LAN. Our Router Expert provides complete instructions for setting up a DNS server, including implementing BIND, configuring a non-authoritative server and creating zone files.Continue Reading

• T1 vs. VoIP for branch office connectivity

  Learn how to decide between a T1, fractional T1 and VoIP for connecting branch offices.Continue Reading

• WAN optimization and bottlenecks: Is the WAN really the weakest link?

  "How much traffic" is no longer a good enough measure of WAN bandwidth. In this tip, Carrie Higbie looks at how today's ever-increasing expectations for data transfer rates require increased attention to WAN optimization, and suggests how ...Continue Reading

• Duplex mismatch: Why duplex conflicts plague the network, part 1

  Duplex mismatch problems -- caused by two ends of the Ethernet attempting a full-duplex connection, resulting in packet loss -- simply will not go away. After a decade of plaguing IP networks, duplex conflicts still seem to be the single worst ...Continue Reading

• How to move an SSL certificate between Exchange servers

  SearchExchange.com contributor Serdar Yegulalp provides step-by-step instructions on how to move an SSL certificate from one Exchange server to another, and explains a couple of gotchas to watch out for during the process.Continue Reading

• Security and the TCP/IP stack

  Each layer of TCP/IP has security mechanisms, protocols, and applications. This tip describes the more popular ones that are associated with each layer of TCP/IP.Continue Reading

• Five steps to stamp out unsafe Wi-Fi use

  Lisa Phifer helps dispel the top myths of wireless security and explains five steps that network administrators can take to lead their users toward safer Wi-Fi usage.Continue Reading

• SMB wireless LAN setup

  Advice for setting up a WLAN for a SMB.Continue Reading

• Reducing false positives in network monitoring

  Network managers need to be aware of the importance of choosing the right tool to monitor their system's internal counters. In this tip, Brien Posey narrows in on alert mechanisms for Windows servers and helps you understand how to reduce false ...Continue Reading

• OpenNMS, an introduction: Affordable network management

  Open source expert Maria Winslow brings network managers up to speed about the free open source enterprise-grade network-management system OpenNMS.Continue Reading

• IEEE 802.3at: Power over Ethernet plus

  802.3af Power over Ethernet (PoE) has been widely adopted for powering VoIP phones, wireless access points and a number of other network-connected products. But it provides a limited amount of power. In this tip, David Jacobs investigates the latest...Continue Reading

• VPNs: Fundamentals and basics

  VPNs are discussed in this introductory tip on the fundamentals of virtual private networks.Continue Reading

• Content Delivery Networking: an introduction

  Doug Downer gives an overview of Content Delivery Network (CDN) technology and its components, which bring together the functionality of file access, caching, multimedia delivery and application processing.Continue Reading

• Why is the cable supporting my LAN experiencing abnormal attenuation?

  Why is the cable supporting my LAN experiencing abnormal attenuation?Continue Reading

• Configuring and troubleshooting wireless LAN clients

  An understanding of wireless LAN (WLAN) client and WLAN access point communication mechanisms is critical to anyone attempting to initially connect or troubleshoot a WLAN connection. In this tip, Robbie Harrell discusses some of the issues that can ...Continue Reading

• Securing your Layer 2 network: Don't overlook the basics

  Before dropping substantial cash on a fancy surveillance system, most sensible home owners would ensure that their doors and windows were locked. Similarly, there are simple security measures you can take to configure your systems for Layer 2 ...Continue Reading

• Understanding network traffic flow analysis

  Network traffic flow is often compared to highway traffic flow. In this tip, Lindi Horton shows parallels between those two worlds and explains why traffic flow analysis is such an essential piece of knowledge for engineering a network.Continue Reading

• Best practices for network management in the non-profit world

  Discover how the Washington, D.C.-based National Parks Conservation Association developed their network management solution to ensure network uptime and availability.Continue Reading

• Using Snort, Nessus and Tripwire for network security

  Why pay a proprietary vendor a ton of money for a security application you can get for little or no money? In this tip, learn the pros and cons of open source network security tools Snort, Nessus and Tripwire.Continue Reading

• IP network design, part 4: LAN design

  This final section of the IP network design series relates to the issues encountered with campus LAN design. The benefits of Ethernet switching over a traditional hub environment are first explained. The motivation behind the deployment of virtual ...Continue Reading

• Certifications that will earn you the most money

  Ed Tittel takes a look at the five network certifications that earned the most money in 2005.Continue Reading

• IP network design, part 3: Designing the WAN

  The wide area network (WAN) is the single biggest contributor to a corporate network's cost of ownership. Therefore, this is the area where the cost-versus-performance tradeoff is most pronounced and most critical. This article explores the various ...Continue Reading

• Implementing software restriction policies

  This tip explains how you can use software restriction policies to keep your workstations in pristine shape and cut down on help desk calls at the same time.Continue Reading

• Router Expert: Initial configuration of a Cisco 1200 802.11g WLAN access point

  Our router expert continues his series on building a secure wireless LAN with a Linux base. This article explains how to utilize a single Cisco 1200 series access point to provide access to three different IP network segments using VLANs and ...Continue Reading

• LAN connectivity problem: Blame DNS, NIC or firewall?

  ITKnowledge Exchange member "BinooDas1234" had connectivity issues with a troublesome LAN, and fellow techies jumped in to help out. But does the answer lie in the DNS configuration, the NIC drivers or elsewhere? Here is a portion of the ...Continue Reading

• IP network design, part 2: The IP addressing plan

  The IP addressing plan is the foundation upon which a successful logical design is built. Part two of this tip explains how to formulate a scalable IP addressing plan that can support the network as it grows.Continue Reading

• IP network design, part 1: Fundamental principles

  A competent network design is the foundation upon which all successful network implementations are built. This is the first of four articles that focus on the design of IP-based networks, due to the prevalence of IP as the de-facto standard desktop ...Continue Reading

• OSI: Securing the Stack, Layer 5 -- session hijacking

  To help secure your systems against session hijacking, this tip walks you through the steps hackers use to hijack active sessions and take over your network. You'll also learn how to detect and prevent session hijacking attacks, a major security ...Continue Reading

• Making sense of Windows routing tables

  When routing packets across a network, things do occasionally go wrong. In these situations, it is helpful to be familiar with the Windows routing tables. Routing tables dictate the flow of packets from the machine in question. This tip will show ...Continue Reading

• Network security checklist

  While 100% security is hardly a possibility, there are several things that you can do to make your network more secure. Learn about them with this network security checklist.Continue Reading

• VRFs and routing

  Doug Downer continues his series about VPN routing and forwarding instances focused on the task of configuring and verifying a VRF scenario with a requirement for separate customers on a shared device. In this tip, he shows how to configure a method...Continue Reading

• Router numbers

  Many of the routing protocols implemented in Cisco's IOS require a number to follow the command that enables the routing protocol in question. If you're new to routing, these numbers can be a little confusing, as they mean something different to ...Continue Reading

• Wireless LAN security: 802.11i

  What is 802.11i, and is it really practical for you to implement in your organization? Robbie Harrell explores how the new wireless standard can improve security -- and reasons why you may want to switch to 802.11i or stick with WPA.Continue Reading

• Router Expert: Building VLAN interfaces in Linux and IOS

  Segmenting a wireless LAN with VLANs can increase security. Find out from our router expert how to support VLAN interfaces in Linux and Cisco IOS.Continue Reading

• Why do we need the MAC address if all Ethernet connections are done via IP address?

  Continue Reading

• Cache poisoning attacks and how to prevent them

  Want something scary to think about? A compromise of your name servers could cut you off from the Internet or redirect your customers to a competitor. It could even shunt sensitive electronic mail through an intermediate mail server or reroute your ...Continue Reading

• What is difference between a WINS server and a DNS server?

  Continue Reading

• VPN security: Where are the vulnerabilities?

  SOX compliance mandates have pushed organizations to deliver end-to-end VPN security. This means that the VPN itself is no longer enough. Robbie Harrell explains how organizations can apply security policies to the VPN in this tip.Continue Reading

• How do I open port 177 on my router so that other clients can get a GUI display of my server remotel

  Continue Reading

• Router Expert: Building 802.11Q VLANs

  Network segmentation can be a great way to increase security. This article covers segmenting with VLANs and the 802.1Q standard.Continue Reading

• Understanding the differences between IDS and IPS

  We all know that the Internet is a haven for cyber criminals who use the connectivity to launch an unprecedented number of attacks against enterprise networks. IDS and IPS have been developed to combat these threats, but they are not one in the same...Continue Reading