Networking Mini Case Studies

Extending a Network

A client in Baldoyle contacted us. They had two new offices built adjacent from their main car park. As part of the building contract these two new offices had cabling preinstalled. Everything was in place, the cabling and all the network points. The computers were installed but none of them were able to connect to the network.

The clients at this stage were suspecting the cabling from their main office block had exceeded the maximum distance allowed and dreaded the thought of any "rip-out-and-replace-solution". They wanted a fast, reliable and economical solution. We examined their cabling and network setup and found that their problem could be resolved by using a simple high-quality switch. Switches can act like repeaters since they regenerate the data so that is it sent out from the switch as it's original strength.

The new switch was installed and their two new offices got reliable network connectivity.

No Access to FTP Sites

An architectural design consultancy firm in Rathmines contacted us. One of their employees could no longer access any FTP sites of their business partners. (FTP sites are used to transfer very large files that would not be practical to share via email). Six weeks previous they were able to access these sites fine. We asked them what has changed recently. They had got a new firewall installed on their network. We looked the firewall settings and TCP ports 20 and 21 were disabled. These ports allow for all inbound and outbound FTP traffic. We created a firewall rule to enable these ports and then got the client to retry access the site. Access was now possible.

Cannot Access Shared Files

A healthcare services company contacted us from Dundrum. They had a peer-to-peer network of 4 computers. One of these computers called \\Office-Main could be accessed from all computers. However, they recently acquired a new laptop that could not access any of the shared files at all. We tried pinging the \\Office-Main computer successfully but could not access it by name. We then checked the lmhosts file on the new laptop. It did not have the lmhosts files configured to provide IP address-to-Netbios name mappings. Once the lmhosts file was configured correctly, access was now possible.

Cannot Access Windows 2003 Server

One Monday morning we received a call from an airfreight logistics company in Santry. For some reason, all of their users had lost access to their Windows 2003 server.

We pinged the server from one of the workstations to receive a "Request Timed Out" message. We checked the NIC (network interface card) on the back of the server and notice that one of the LED lights is glowing amber. The server's desktop was available and the keypad and mouse are responsive. Other hosts on the same subnet of this server were accessible.

The amber glowing LED on the NIC indicated to us that it needed to be replaced. After installation of a new card and reboot of the server, all the users had restored access to the server.

VPN Setup

A solicitors firm in Dublin 2 contacted us. They had recently acquired a smaller practice and they wanted the data of both practices shared. Both firms had access to high-speed broadband. They wanted a link that would be secure and reliable. They had got some advice that only the firewall rules would have to be changed to share data.

In this case, we strongly suggested against changing the firewall rules, as they wanted a continual data exchange between the two networks. "Poking a hole" in the firewall for long-term data transmission would compromise the security of each individual network and the security of the data transmitted.

We installed a VPN (virtual private network) to facilitate data exchange. A VPN is one of the safest and most reliable ways for two businesses geographically distant from one another to share data.

Intermittent Internet Connection

A school from Rathmines contacted us. They reported an intermittent internet connection problem. Some days the internet connection in their offices and classrooms would be fine. Other days, the connection would go down for apparently no reason whatsoever. Our technicians went onsite to investigate the problem. Using their diagnostic tools they found there was two routers on the network both acting as DHCP servers. For their class of network, two DHCP servers were totally superfluous to their needs. It was a bit like having two sets of traffic lights at the same junction. One set which would show green and another set which would show red simultaneously. We removed the second router and they now got a constant and stable internet connection.