Ask the Experts

Ask the Experts

• 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

• IP addressing in IPv6

  Understand the differences between network IP addressing in IPv6 and IPv4. Our expert, Silvia Hagen, explains the advantages and disadvantages of calculating IP addresses for each version.  Continue Reading

• What environmental factors cause switch connectivity to fail?

  If the power on your network's switch is fine, but the connectivity is not, ask yourself these questions posed by our switching expert to troubleshoot for environmental issues that may be causing this connection failure.  Continue Reading

• Are there beginner certifications to take before Cisco's CCNA exam?

  Even though Cisco's CCNA certification is a beginner course, if you're new to networking, passing this exam is daunting. Try the starter certifications our Cisco expert suggests in this piece of advice.  Continue Reading

• How can I pass the CCNA exam without spending any money?

  Is there any way to pass the CCNA exam without spending any money? Find out from our Cisco certification expert, David Minutella.  Continue Reading

• Why do Linksys WMP300N wireless cards have three antenna connectors?

  Before you make a larger antenna for your wireless network card, know how the Linksys WMP300N connects to its antenna, and understand why it has three connectors.  Continue Reading

• Can building T3 lines using satellite be cheaper than a carriers'?

  Would building your own T3 leased line be cheaper than a standard carrier's service? Our networking fundamentals expert explains this and how a large capacity link reacts over satellite communication, in this Ask the Expert response.  Continue Reading

• Differences between WLANs, Wi-Fi and WiMax

  Wireless networking expert Lisa Phifer explains the differences between WLAN, WiMax and Wi-Fi and provides an excellent tutorial on what separates Wi-Fi from WLAN.  Continue Reading

• LANs vs. WLANs: Which network designs are used for each company size?

  Which network design is easier to implement, LANs or wireless LANs? Our network administration expert explains this and which designs best fit particular functions and areas of your organization.  Continue Reading

• How can I block my competitor's IP address range from my website?

  Are you looking for free network tools to find an IP address range? This advice from our security expert shows you whois tools available to you and then explains how to block these ranges from viewing your Web resources, in this expert response.  Continue Reading

• Controlling network access by MAC address restriction on wired networks

  If you've used MAC address restriction to control your network access on your wireless router, can you extend this to your wired network? Our security expert explains in this response.  Continue Reading

• Why are patch panels required for cabling networks?

  When cabling networks, you may wonder why it's a requirement to have patch panels and why they aren't connected to switches. This expert response explains why and how they're used in a rack with multiple switches and ports.  Continue Reading

• How to configure Cisco's 3750 Layer 3 switch for fallback IOS booting

  Our switching expert explains how to configure your Cisco 3750 Layer 3 (L3) switch to automatically boot your system from the IOS kept on the TFTP server, in this response on fallback booting.  Continue Reading

• How to boost the wireless ranges of laptops

  Learn how to boost the wireless range of a laptop computer so that you can reach the access point of a service provider in this how-to by wireless networking expert Lisa Phifer.  Continue Reading

• Which exams must I pass for CCVP and CCNP recertification?

  To recertify for Cisco's networking certifications, CCNP and CCVP, you have a these options.  Continue Reading

• What software monitors and locks users from accessing my router?

  Learn which software programs monitors and locks unauthorized users from accessing your router for Internet use in this expert response with our network security expert, Michael Gregg.  Continue Reading

• On a full-duplex T1 circuit, what's the bandwidth speed in both directions?

  Find out if a full-duplex T1 circuit splits its bandwidth between the TX and RX directions.  Continue Reading

• Which wireless client vendor will keep my network from disconnecting?

  Learn which vendors provide universal wireless clients for Windows laptops that may address network and Internet disconnects as well as missing profile problems, in Ask the Expert response from Lisa Phifer.  Continue Reading

• Why do we need IP security at the network layer?

  Learn why IP security (IPsec) is needed at the network layer -- otherwise known as Layer 3, or L3, of the OSI model. Our enterprise networking security guru explains.  Continue Reading

• What power supply problems do 802.11n wireless networks pose?

  The power supply requirements demanded of 802.11n wireless networks won't be affordable for enterprises until the IEEE standard and supporting network hardware are approved and have caught up. Here are some options for fixing this problem while you ...  Continue Reading

• What is the role of a network administrator?

  Learn the differences and job duties of network and system administrators in this expert response.  Continue Reading

• Simulators for practicing Cisco's CCNP routing and switching exam

  To practice for the CCNP routing and switching exam our Cisco expert, David Minutella, recommends this simulator.  Continue Reading

• How can I resolve this remote worker's VPN connection problem?

  Our network administration expert explains why this remote worker cannot connect to their company's virtual private network (VPN) through their Linksys router, in this expert response.  Continue Reading

• How can I be sure no one is hijacking or hacking my WAP?

  Learn how to protect yourself from hackers and wireless access point (WAP) hijackers in this advice from our networking expert.  Continue Reading

• Will mixing 802.11g and n APs in the same network cause conflicts?

  Learn how combining both 802.11g and 802.11n access points (APs) affects network behavior, in this expert response.  Continue Reading

• How do I set up multiple VLANs on a single switch?

  Learn how set up VLANs on one switch and replicate them throughout the network in this response.  Continue Reading

• Can you connect multiple computers to one printer without a router?

  Find out how to connect multiple computers to one print station in this expert response.  Continue Reading

• How can I use VLANs and NAT to get around the need for a static IP address?

  Learn how to use a VLAN and NAT to get around static IP address designation problems.  Continue Reading

• How can I get reliable voice data (VoIP QoS) through ISDN circuits?

  Though QoS policies don't work in regards to ISDN, learn how to get reliable VoIP voice data, in this advice from network administration expert Lindi Horton.  Continue Reading

• What correlation does ping latency have with high server activity?

  Our network administration expert explains which metrics provide visibility into what's going on at peak activity levels in order to optimize network performance in this expert response.  Continue Reading

• How each wireless technology differs: Wi-Fi, WiMax and WLANs

  This expert response explains the difference between wireless technologies like Wi-Fi, WiMax and WLANs.  Continue Reading

• What is the main advantage of having a Layer 3 switch over a router?

  In this Q&A, our router expert, Sudhanshu Gupta, talks about the advantages of having an L3 switch over a router.  Continue Reading

• What does a subnet do?

  Learn about the role of the subnet in a network, including switching and packet recognition.  Continue Reading

• What's the difference between VPN pass-through and multi-tunneling?

  Learn why multi-tunneling is better than VPN pass-through and how IPsec plays a role from an expert.  Continue Reading

• What is a genetic algorithm and where can I learn more about them online?

  Learn about genetic algorithms as well as where to find online resources for understanding them.  Continue Reading

• Minimum and maximum Ethernet frame sizes

  In this Q&A, our network administration expert addresses Ethernet frame sizes, as well as minimum and maximum sizes of Ethernet frames that carry IP and ICMP.  Continue Reading

• Will 25b army school help me get a job or CCNA certified?

  Find out if 25b army school will prepare you for the CCNA exam or help you get a career.  Continue Reading

• What's the difference between the two CCNA certification tracks?

  Find out which test track you should take when getting CCNA certification in this expert response.  Continue Reading

• How does IPv6 subnetting work in LAN and VLAN network design?

  Learn the differences between IPv4 and IPv6 addressing and subnetting for local area network (LAN) and virtual LAN (VLAN) design in this expert advice.  Continue Reading

• Problem connecting to virtual private network (VPN) through Linksys router

  When your remote worker has problems connecting to your virtual private network (VPN) only when they go through a Linksys router, use these steps to resolve the connection issue.  Continue Reading

• Wireless networking problems combining 802.11n and 802.11g APs cause

  Will using both 802.11g and 802.11n access points cause problems with your wireless network? Learn from Wi-Fi expert Lisa Phifer how to ensure peaceful coexistence between old and new clients sharing the same frequency band, in this answer.  Continue Reading

• What's the best way to prepare for the CCNA exam alone?

  Find out what resources you'll need to pass the CCNA exam without taking any classes.  Continue Reading

• Why haven't I received my CCNA certification? I passed the test.

  Find out who to contact when your CCNA certification hasn't arrived from Cisco.  Continue Reading

• How to set up a VLAN on multiple switches

  Learn how to establish a VLAN over multiple routers in this response from a networking expert.  Continue Reading

• Can a Layer 3 switch replace a router for WAN connections?

  Learn how to use a Layer 3 switch in place of a router for WANs from a routing expert.  Continue Reading

• How can I implement MAC address binding between switches?

  Learn what configuration you need to implement MAC binding across switches in this expert response.  Continue Reading

• Where is Carrie Higbie's most recent advice?

  To view networking infrastructure and project management expert Carrie Higbie's latest advice, see her Public Profile on the IT Knowledge Exchange.  Continue Reading

• Why isn't CCNA certification enough to get me hired?

  Learn why CCNA certification won't guarantee you a job and what you can do to secure a position.  Continue Reading

• In IPv4, do private address ranges have a default subnet mask?

  In this expert response, Silvia Hagen explains the relationship between private IP address range and default subnet masks. She also informs us about new address types coming up in IPv6 that will make subnetting and addressing easier.  Continue Reading

• How to implement VLAN switches across wireless LAN (WLAN) links

  Learn different methods of creating virtual LANs (VLANs) on a wireless LAN (WLAN) in this expert response from Lisa Phifer.  Continue Reading

• How can I use a Layer 3 switch for voice routing?

  Learn how to use a Layer 3 switch for voice routing in this expert response from a switch expert.  Continue Reading

• Are there 802.11n wireless antenna extenders to boost outdoor signal?

  Learn how to increase Wi-Fi range when multipath reflections aren't enough in this advice from our wireless networking expert.  Continue Reading

• What does a QM FSM error signify on a VPN Concentrator?

  Learn how to solve a QM FSM error when working on a LAN-to-LAN VPN from a network security expert.  Continue Reading

• How does WiMAX compare to other wireless broadband services?

  Learn about WiMAX and similar WAN technologies, such as 3g, in an expert response from Lisa Phifer.  Continue Reading

• How to block porn with ISA-server firewalls

  Learn how to block unwanted content, including dangerous messengers and porn, from your server.  Continue Reading

• How many more users will 802.11n wireless access points support?

  Learn about the upgrades in 802.11n wireless access points; including speed, data rates, and bandwidth from wireless networking expert Lisa Phifer.  Continue Reading

• What security measures are recommended for each level of the TCP/IP model?

  Find out where to put security measures and what options are available in the TCP/IP model in this expert response from Michael Gregg.  Continue Reading

• How to connect wireless networks for printing capabilities

  Get step-by-step instructions on how to connect wireless routers so that you can print wirelessly and stay connected to the Internet in this expert response from Lisa Phifer.  Continue Reading

• What is the Free Public WiFi network I keep seeing in public places?

  If you've tried connecting to Free Public WiFi without success, this expert response explains what the network is and why it doesn't work.  Continue Reading

• Accessing printers on a LAN while connected to a WLAN

  Learn how to connect printers on a LAN to users on a WLAN and IP address assignment problems between networks from wireless expert Lisa Phifer.  Continue Reading

• How to maintain corporate VPN connection while printing to a private network

  In this advice from our wireless networking expert, learn how to maintain a corporate VPN connection while printing to a private network.  Continue Reading

• How to locate the lost IP address of an access point (AP)

  Find out how to find a missing IP address for an access point (AP) from network security expert Puneet Mehta.  Continue Reading

• How can I prevent collisions on my network?

  Learn about network collisions and how to prevent them with networking expert Chris Partsenidis.  Continue Reading

• What do routers use MAC addresses for?

  Find out what routers do with MAC addresses and why they're needed in this response from routing and switching expert Sudhanshu Gupta.  Continue Reading

• Inter-VLAN routing with a LAN and WAN on a single router

  Find out how to have VLAN and LAN/WAN networks on a single router from industry expert Sudhanshu Gupta.  Continue Reading

• What are recent security developments for MIPv6?

  Learn about MIPv6 security and if it's safe for public Internet deployment in this expert response from Silvia Hagen.  Continue Reading

• How to use IPv6 on an IPv4 backbone

  Learn how to use IPv6 on an IPv4 backbone without dual stacking in this expert response from Silvia Hagen.  Continue Reading

• Will different wireless card link speeds cause network latency?

  Our wireless networking expert, Lisa Phifer, explains how to avoid network latency when wireless network cards with different maximum link speeds slow down your WLAN.  Continue Reading

• What makes a WAN different from a LAN and MAN?

  Learn the basics of networking in this expert explanation of the differences between WANs, LANs and MANs -- how they connect and which protocols they use.  Continue Reading

• How do I increase network signal strength over a large distance?

  Learn how to establish a wireless network over a large area by incorporating access points or antennas in this expert response from Lisa Phifer.  Continue Reading

• What HIPPA-compliant software would you recommend for online medicine?

  Learn about HIPPA compliant telemedicine software in this response from a network security expert.  Continue Reading

• Bandwidth calculations for wireless networks supporting VoIP

  When designing a wireless enterprise network supporting VoIP, learn how to calculate bandwidth amounts per user and the number of calls a single AP can support simultaneously. This expert response also features multiple VoIP call bandwidth ...  Continue Reading

• How much harder is the CCNA from the Network+ exam?

  Learn the differences between the CCNA and Network+ exams as well as the different certification options available from Cisco certification expert David Minutella.  Continue Reading

• What is a logical network? How do you improve one?

  Learn what logical and physical networks are and how to improve them, in this expert response with networking fundamentals expert, Chris Partsenidis.  Continue Reading

• Buying your own WAPs vs. Internet service provider's wireless routers

  Should you buy a wireless router from your Internet service provider or buy our own WAPs? Our wireless networking expert gives a case for each in this response.  Continue Reading

• What is 802.11n Greenfield mode used for?

  Understand what 802.11n high throughput (HT) mode, or Greenfield mode, is in this explanation from our wireless networking expert.  Continue Reading

• Are my Cisco certification course books too outdated to use?

  If your Cisco certification course books are nine years old are they too outdated? Our Cisco certification expert explains their relevance to the exams and advises why they might be good to keep.  Continue Reading

• To simulate voice over IPSec VPNs which simulators work?

  Learn which simulators you can use to simulate voice over IPSec VPNs in this advice from our network security expert.  Continue Reading

• How to set passwords on folders in Windows 2003 servers

  Learn how to configure file and folder security on a Windows 2003 server in this expert advice from Puneet Mehta, our network security expert.  Continue Reading

• Does each routing protocol have a different routing table?

  Learn from our routing and switching expert, Sudhanshu Gupta, whether different routing protocols such as RIP and IGRP have different routing tables or number of columns for specifying information related to it.  Continue Reading

• What are the best methods for handling rogue access points?

  Our network security expert, Michael Gregg, explains how to enforce network policy and handle rogue access points (APs) in this expert response.  Continue Reading

• How to route L3 switches for a serial LAN design

  Learn from our routing and switching expert how to configure a Layer 3 switch in a serial LAN design to route from the interface to the last machine, in this Ask the Expert Q&A.  Continue Reading

• How can I configure 10 VLANs with 5 unmanaged switches?

  Given a Cisco Layer 3 (L3) switch and 5 unmanaged switches, learn how to create 10 VLANs from our routing and switching expert, Sudhanshu Gupta.  Continue Reading

• How to configure ISDN and backup leases on routers

  Routing expert Sudhanshu Gupta explains how to configure ISDN and backup leases on routers in this expert answer.  Continue Reading

• What is broadcasting and which switch will fix timed-out requests?

  Broadcasting is defined by our routing and switching expert as he explains which network switch resolves time-out requests, in this response.  Continue Reading

• How can I finish Cisco's CCIE security certification in time?

  Under deadline to get a Cisco Certified Internetwork Expert (CCIE) security certification? Use this advice from our expert to help you pass your exam in time.  Continue Reading

• What are three vital pieces of criteria used to evaluate a network?

  Learn what to look for when evaluating a network, including common problems with architecture.  Continue Reading

• How do I configure two leased lines in one router?

  Our routing and switching expert explains how to configure two leased lines in one router, in this Ask the Expert answer.  Continue Reading

• IP address configuration to connect Layer 3 switches to ports

  Our routing and switching expert explains the IP address configuration needed to connect a Layer 3 (L3) switch to a port, in this response.  Continue Reading

• How to interpret test scan results to assess network vulnerability

  Once you've run some test scans with a network tool, how do you interpret the results to assess network vulnerability? Find out in this Ask the Expert response with our enterprise network security expert.  Continue Reading

• What commands allow network traffic to pass through PIX firewalls?

  The PIX firewall can secure networks but you need to allow access to the right people. Learn which commands get network traffic flowing, from security expert Puneet Mehta.  Continue Reading

• What's the Ethernet packet collision rate in Windows OS?

  Is there a way to know the Ethernet packet collision count/rate in a Windows OS? Find out in this answer from our networking fundamentals expert, Chris Partsenidis.  Continue Reading

• For an SMB firewall, what features should I look at?

  Which features should you look at when choosing a SMB firewall? Find out in this expert response with our network security expert.  Continue Reading

• What can we expect in an 802.11n Wireless LAN standard implementation?

  At what stage is 802.11n implementation in, and what changes can we expect to see with it? Learn about the standard from wireless networking expert Lisa Phifer.  Continue Reading

• Can you create a persistent wireless connection to a wired LAN?

  Can you create a persistent wireless connection to a wired LAN? Find out from our wireless networking expert, Lisa Phifer.  Continue Reading

• Why are IPv6's IP addresses in hexadecimal formatting?

  Why would IPv6 use hexadecimal formatting if it's so user unfriendly, and what sort of workarounds are there to make IP addressing easier? Find out in this expert answer.  Continue Reading

• Understanding VLAN implementation and IP address assignment

  Learn how to create and configure a VLAN in this response from a network administration expert  Continue Reading

• What should I know before implementing a packet sniffer?

  Before implementing a packet sniffer learn what you need to know before putting one into your network and where it should go.  Continue Reading

• To practice for my CCNP, what's the best simulator?

  What should you use to practice on for your CCNP exam? Find out the best simulator from our Cisco certifications expert.  Continue Reading

• Cisco Certified Internetwork Expert (CCIE) prerequisites and average earnings

  Our Cisco certification expert, David Minutella, explains what the Cisco Certified Internetwork Expert (CCIE) requires of you and what the average earnings are, in this Ask the Expert response.  Continue Reading