I managed to get 24 Juniper Olive routers running on my workstation without any issues. But because I do allot of other things on my workstation as well, I have to reboot it every once in a while.

It’s a pretty time-consuming job to power off and power on the Olives every time I reboot and suspending them in VMware doesn’t always work that well. That’s why I decided to give my Olives a more stable environment by putting them on a dedicated server which won’t be rebooted that often.

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A GUI interface is great for novice administrators but is cumbersome if you have to perform the same task over and over again. Command line tools can be more efficient than GUI tools. Dnscmd.exe is one of the support tools from Support.cab, which is located in the support’tools directory on the Windows 2000 CD.
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In order to configure TCP/IP settings such as the IP address, Subnet Mask, Default Gateway, DNS and WINS addresses and many other options you can use Netsh.exe.
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Introduction

Dynamic Host Configuration Protocol (DHCP) is a core infrastructure service on any network that provides IP addressing and DNS server information to PC clients and any other device. DHCP is used so that you do not have to statically assign IP addresses to every device on your network and manage the issues that static IP addressing can create. More and more, DHCP is being expanded to fit into new network services like the Windows Health Service and Network Access Protection (NAP). However, before you can use it for more advanced services, you need to first install it and configure the basics. Let’s learn how to do that.

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The Cisco Unified Communications Manager Express (CUCME) is the new brand name given by Cisco to the older Call Manager Express (CME) system. The concept is the same however: IP Telephony software running on Cisco routers. Therefore, the CUCME is a normal Cisco router (models supported are 1800, 2800, 2900, 3800, 3900 series) with a special IP Telephony software (call manager software) installed on the router’s flash memory. The CUCME system serves as the call control node to facilitate IP Telephony communications in a small to medium size Enterprise.

Usually there is a single CUCME system in each LAN network, with several IP phones connected on the LAN switches. An enterprise with several sites connected over a private IP WAN network can establish full IP voice communications between sites by configuring H323 communication between each CUCME router. A simple example with a two-node topology is shown below.

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The Cisco CallManager Express is a product under the Unified Communications Products suite of Cisco. In the past it was known as CCME (Cisco Call Manager Express) but now the new name is Cisco Unified Communications Manager Express.

It is an IP Telephony system (IP PBX) for small to medium size businesses of up to 250 IP phones capacity. Basically, a CallManager Express system is a normal Cisco Integrated Services Router (models 1800, 2800, 3800) which has the CallManager software installed on the router’s flash memory. The router hosting the callmanager system can work also as normal Internet Border router or as WAN Router connecting to other enterprise sites. The CallManager software provides call control and IP telephony functionality to internal IP phones. For connectivity to the PSTN network, voice interface cards can be installed on the CallManager router (such as voice BRI, PRI etc).

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Continuing our series of posts on IP Telephony and VoIP, here is Part 3 of the tutorial:

Is IP Telephony Implemented Easily ?

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Continuing our series of posts on IP Telephony and VoIP, here is Part 2 of the tutorial:

Can an IP Telephony System be connected to the public telephone network

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Although this is a Cisco networks dedicated blog, I decided to start a series of tutorial posts about a general technology which is not directly related to Cisco but it is a field in which Cisco is again a major player. This is IP Telephony and Voice over IP (VoIP). The two terms, IP Telephony and VoIP, are related around the same concept but in my opinion they are not exactly the same thing. Many people refer to these two terms interchangeably but they are not exactly the same. So, before moving on lets clarify the difference between IP Telephony and VoIP.

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In addition to IPSEc VPN support, Cisco firewalls support also the SSL Web VPN technology for providing access to resources for remote users. The main difference between IPSEc VPN and SSL VPN is that the first one requires a VPN client installed on the user’s computer while the SSL VPN requires only a secure browser (HTTPs). Another difference is that IPSEc VPN provides full network connectivity to the central site for the remote user with the ability for the user to have full access to applications just like local LAN access. On the other hand, SSL VPN provides limited application access compared with IPSEc VPN. The applications that can be accessed by SSL VPN include Internal websites, Web-enabled applications, NT/Active Directory file shares, E-mail proxies, including POP3S, IMAP4S, and SMTPS, MS Outlook Web Access, and port forwarding access to some other TCP-based applications.
The diagram below shows a high level network topology for SSL VPN connectivity:

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