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How To Determine Your New DEF CON Group's Number

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  • FAQ/Guide: How To Determine Your New DEF CON Group's Number

    How To Determine Your New DEF CON Group's Number
    August 25, 2018 by aprilwright

    One of the most frequently asked questions and concerns for new DCGs is in regards to naming of their group.

    We HIGHLY RECOMMEND that you DO NOT: buy domain names, register social media handles, or create branding until your group is listed on the website.

    This recommendation extends past receiving the email from us stating that a request has been made to add your group to the website. The "request to be added" email is NOT final confirmation of establishment of your group. Only being on the website is confirmation.

    This post is intended to help new group leaders avoid spending time, effort, and/or money on branding that may need to be changed later.

    As new groups form, we have to evaluate the naming convention of the group for accuracy and fit within the numbering and naming system rules.

    It is not fun for us to have to tell a new group leader (who has already registered a Twitter account, bought a domain name, and designed a logo) that the name they assumed they would have e.g. DC111 is really going to be DC112345! It unfortunately happens all the time, and can cause disappointment, so we want to prevent that.

    We do not want you to go through any unnecessary work or spend any money on domain names only to have to change them!

    In addition, sometimes the Signaler who answers the dcgroups emails will ask for the group to be added to the site, send you a notification as such, and a secondary check by the larger team will determine that the name needs to be changed.

    It is therefore advisable to wait until your group is *officially listed on the site* before doing anything that may cost money or confuse your community.

    We can make changes to your listing after you're officially an organized DEF CON Group, but you cannot get your money back from a domain name you purchased that is no longer appropriate!

    Many groups want to choose their own name. We get lots of requests for DC0101010101 or DC042...

    The reality is that group names are based on telephone dialing codes, as dialed from the USA. This is to make sure group names are unique. If we have two DC123 groups, and one is in the USA and one is in Antarctica, that would be very confusing.

    The International Telecommunication Union (ITU) has established a comprehensive numbering plan, designated E.164, for uniform interoperability of the networks of its member state or regional administrations. It is an open numbering plan, however, imposing a maximum length of 15 digits to telephone numbers. The standard defines a country calling code (country code) for each state or region which is prefixed to each national numbering plan telephone number for international destination routing. You can read more about this here:

    The general rules for dialing internationally are:
    For calls to most countries, this means: 011 + country code + phone number

    For calls to countries within the North American Numbering Plan, this means: 1 + area code + 7 digit local number, same as dialing a US state to state call

    So, if I dial 1-312-555-5555 to reach Chicago Illinois USA, the Chicago DC # would be DC312. North America uses non-overlapping area codes, so if I were to dial Edmonton, Canada from the US, I would dial 1-780-555-5555. 780 does not exist as an area code within the US. Since there is no 780 area code within the USA, 780 is unique. Edmonton would be DC780. There is no other DC780 other than Edmonton.

    The confusion really starts with international groups outside North America. This is because of Country Codes and sometimes City Codes being required in addition to area codes.

    Let's look at an example. 816 is an area code used to dial Missouri, USA. 81 is ALSO the international code to dial Japan and 6 is the local area or city code to dial Osaka (i.e. 816). Therefore, by preceding Osaka's 816 dialing code with the international dialing prefix 11, we get DC11816. This makes it clear that it is the Osaka group, and not a Missouri group.

    If you want, you can search here - Choose "United States" as the source, enter your country, scroll down to find your city, and you can then figure out your dialing code (this is what we do)

    For a variety of reasons, a second group within a city/country may be desired by local hackers.

    If you want to start a group in Shanghai, and there is another group in Beijing, or if you want to start a group in Brugges (113250) and there is already a group in Brussels (11322), you do not have a problem. They are geographically diverse, and have different dialing codes.

    However, some cities and countries only have one dialing code, e.g. Luxembourg is 11352. If a second Luxembourg group were created, the first / original group that was formed would remain DC11352, and the secondary group would be DC11352-A, any third group would be called DC11352-B, et al. Sure, three DEF CON groups in Luxembourg may seem silly, but it's just an example :)

    Sometimes a group already exists within a single city, for example, Chicago DC312. Chicago is a large city, and there are also student groups on-campus vs public groups.

    In this case, if there is a secondary area code, that can be used. For example, Chicago has an area code of 312 and another area code of 773. Group leaders can apply as DC773 when there is already a DC312, or they can choose to be DC312-A, as the dialing codes overlap.

    We admire your go-getter attitude in that you want to have the website and social media accounts ready to go when you apply to be a group, but doing so is not always in your best interest.

    If you are an international group, we recommend waiting to register or purchase anything with the name of your group until your group name is confirmed by us.

    Remember: You can send us an update request at any time to keep your info current, add social media, links, etc. We love to hear about what you're working on and keeping the site updated with fresh content from the groups.

    Please DO NOT HESITATE to contact us with any questions - we are here to help!!!

    Don't see an answer to your question? Just ask in the main forums thread!
    Last edited by The Dark Tangent; March 26, 2020, 23:57.
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