Y2k Tech: Caller Line Identification and ISPs

January 5th, 2013 by Richy B. Leave a reply »

I’m adding the details of CLI (Caller Line Identification) and usage by ISPs here for archival reasons. Although in 2013, this information should no longer be needed (it was back in 2000ish when I originally wrote it). So please be aware this is massively outdated and probably no longer relevant information, but I like to archive stuff 😉

Most users of the Internet will have experienced what is called Spam. Spam is the term used on the Internet for unwanted email messages that most users receive from time to time. These message are usually trying to sell something in one way or another and many users just ignore them or delete them. To many people though these messages are a source of great annoyance and cause passions to run very high because if not kept in check, then Spam email messages could swamp your mailbox with hundreds of unwanted messages each day. Imagine if this happened with the junk mail you receive through the normal postal system. You would have a pile of mail a foot deep at your front door each morning and you would be straight on the phone to the Post Office to find out how you could stop it, not because it was costing you anything, but because it was very inconvenient and time consuming to sort through. The difference between mail that is delivered through your letterbox and mail you receive over the Internet is that you pay for mail delivered to your computer through your telephone bill because it takes time to download these unwanted messages and the meter is running. Another big difference is that email sent to hundreds of thousands of people via the Internet can be done relatively cheaply and therefore attracts the attention of many unscrupulous individuals.

One of the best methods for deterring Spammers is to insist that our customer’s phone line displays it’s CLI (calling line identification) when accessing our Internet service. This means that we can easily determine the telephone number of the person or company that is abusing our network and take the appropriate action to stop this happening again in the future.

Most Internet Service Providers have either already implemented this policy or are in the process of implementing the use of CLI for the sending of email and the posting to news services.
If a “ISP A” does not do this then many other ISP’s across the globe may well ban mail from “ISP A”‘s service because of the amount of Spam email that originates from “ISP A” service. This could mean that when you send an email to a friend or colleague it is returned to you, not because there is a problem with the address you are sending it to, but because another ISP has taken sanctions against “ISP A” and will not allow mail from “ISP A”‘s servers onto their network as punishment for not maintaining a secure system or a system that may be viewed as being kind to Spammers and abusers of the Internet in general.
So “ISP A” has no choice. Either conform or end up with a system that is unusable.

If you have CLI enabled then you just carry on as normal. If you don’t have CLI enabled you can do one of two things.
1. Call your telephone provider (BT, NTL etc) and ask them to enable CLI on your telephone.
2. If you don’t want to give out you number everytime you use the telephone then it is possible to add a number before you dial “ISP A” ‘s 0845 number that will enable CLI just for this one call only i.e. 1470 in the case of BT customers. So for example “ISP A” number would be 1470 0845 xxx xxxx.
This number can be added to your modem properties so that it is dialled automatically each time you connect to the Internet.
For a Windows 95,98 or 2000 machine, go to “Settings > Control Panel > Modem > Dialing Properties” and tick the box for disabling ” Call Waiting” and add 1470 as the number to be dialled.

If you don’t know if you have CLI enabled or not you could call your telephone provider and ask them. An alternative method would be to call a friend, and then get them to dial 1471 and tell you what message they heard – if they heard your telephone number being read out, then you’ve got CLI enabled, if they don’t they you’ve probably got it disabled.
Please remember that you can connect to the Internet using “ISP A” whether you have CLI enabled or not. It is only for SENDING email that “ISP A” insist that CLI is enabled so that if a Spammer uses “ISP A” to send thousands of Spam messages “ISP A” can easily find him and bar that number immediately from sending mail ever again.
If you are in a situation whereby you cannot enable CLI for whatever reason i.e. you are on a PABX (switchboard) that is not set-up with CLI enabled then you can always use WebMail in order to send email.

This post is over 6 months old.

This means that, despite my best intentions, it may no longer be accurate.

This blog holds over 12 years of archived content - during that time, I may have changed my opinion of something, technology will have advanced (and old "best standards" may no longer be the case), my technology "know how" has improved etc etc - it would probably take me a considerable amount of time to update all the archival entries: and defeat the point of keeping them anyway.

Please take these posts for what they are: a brief look into my past, my history, my journey and "caveat emptor".

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