Coding Horror

I remember my brother being given one of those before packing off on a J1 to the US (or rather, the international equivalent)

It was for calling home every week, had something like £100 on it to start in case he needed to make an emergency call

The clown blew threw the whole balance in the space of a week from calling his long distance girlfriend who dumped him about a week later 😂

Parents told him if he called again he'd be paying the phone bill before they'd buy him a flight home. I think this was the days you got charged for receiving international calls as well

He must have been reversing the charges (and they foolishly let him). You didn't get charged for receiving calls.

So, the ISDN connection was set-up on the Cisco to 'spoof' a permanent fixed-line connection.

Unlike traditional dial-up, ISDN could establish a connection almost instantly.

The original selling-point of ISDN 'spoofing' was it was supposed to be cheaper than a fixed leased-line.

So if a user in Belfast wanted to establish a terminal session to our mainframe in Dublin, it would do so almost immediately as if they were already on our network. The Cisco routers were configured to make the call once it saw a user sending packets to a particular port.

When I analyzed the bills from both Eircom and BT, where were dozens of calls being made per-second between both networks. Standard call cost at the time was about 20p, so imagine that happening dozens of times a second, 24/7 for months.

I really felt totally out of my depth coming from a coding background, using a packet sniffer and trying to decode and monitor what traffic was triggering the connections. It was late one Friday evening and I was about to give up when suddenly I saw some strange traffic on a very unfamiliar port coming through that was triggering the ISDN connection.

Looking up the port, it was one used by tape backup software called Arcserve, which the small provider company set up on the Netware servers in both Dublin and Belfast. It was just a service-advertisement packet, but it was triggering the ISDN to connect.

When I checked how the company filtered the ports on the Cisco to trigger the ISDN, they started with the premise of allowing everything but just putting a deny list of known packets they didn't want to trigger the connection.

WRONG!!!1!! I learnt later that you start from the position of denying everything and only allowing known calls to known ports through. They had gone totally the other way around it - allow everything and provide a deny list. They had totally neglected to filter out the port used by the Arcserve software.

Apparently we weren't the only company 'stung' by so-called exports setting up routers incorrectly for ISDN spoofing and resulting in mega-bucks phone bills. Eircom issued an advisory letter to all it's ISDN business customers later that year.

In retrospect, the company were a small-two man operation in Dublin that were completely chancing their arm when it came to setting up Cisco routers and out of their depth.

And did this lead me to having a successful change of a career-path into Networking and router configuration? Like f*ck it did! It was fun, but no thanks!

Those IBM Token Ring cards were big bucks, especially the 16Mbps version. I place I worked for spent over 2M upgrading a building to use them. This was on instruction of 'Head Office'. Our IT wanted to to use 10 Base T Ethernet. The kicker was the IBM Mainframe was not 100% 'compatible' with them and always had issues. Even after the experts from IBM were flown in from the States to sort it out. We had the IBM hardware division blaming the IBM software division... Another manufacturers mainframe worked fine on the network! Within a year or two 100 Base T had come out and the cards and routers were much cheaper.

True. As late as 2005 I had to get Eircom to install an ISDN line to my house (was in Meath) as we were on what's called a 'group line' shared on the local exchange with five other houses. Great for voice, but even with a 56Kbps modem, you'd be lucky if you got a 9Kbps connection.

In 2005 Eircom at the time said that BB couldn't be installed at my house. So once I got ISDN, I was taken off the 'group line' and suddenly my number was compatible for Broadband, which I ordered the month after I had the ISDN installed.

Crazy times.

I developed an API to be consumed by one of my clients. I sent the API documentation to the client's project manager.

A few weeks later their developers had developed their solution to call my API but were getting invalid request errors. I asked them if they were referencing the correct documentation and they said they were. The version number matched the version I had sent the PM. But looking at their JSON in their requests, they were definitely not matching my spec. It turns out that their PM incorrectly thought I had made mistakes in the document and took it upon himself to make changes without informing anyone or even incrementing the version number of the document.

Final story about ISDN was working as a contractor for the provider of ISDN lines and couldn't get a ISDN line installed in their own building. They said it would take 6 months. In their own building. Name of the building. Telecom house.