Hostnames and usernames to reserve | Hacker News Reader

Hostnames and usernames to reserve

ldpreload.com

206 pointspaulproteus24 comments

When github used to host "pages" under github.com I remember registering "blog.github.com" (and reporting obviously). If you take the social-engineering into account the list should be made long: login, support, status, help, ...

Just to say, the list could be made much longer (eg: login)

Seems PayPal also missed this memo: https://www.paypal.me/support https://www.paypal.me/download https://www.paypal.me/signup

Here are some that I've reserved for my own web app, now inclusive of RFC 2142:

https://gist.github.com/zachrose/30862a11857a31242d60

Thanks, this was very informative.

I wonder how the pull requests for the public suffix domains are being checked. Can somebody use it as an attack surface by adding the victim's domain in that list and effectively blocking their website from setting cookies?

Faced with similar issues, I maintain a python library called python-usernames[1] with list of closed to 400 reserved words[2].

Publishing this as a library helps a lot collecting the wordlist over time and be able to use the same list in all my projects.

[1] https://github.com/theskumar/python-usernames

[2] https://github.com/theskumar/python-usernames/blob/master/us...

I would suggest adding "autodiscover" to the list of disallowed hosts. It is used by Microsoft Outlook and Exchange ActiveSync clients (e.g. in smartphones) to automatically detect the correct server settings.

Also, you should include the name of your service itself, especially if users can produce content.

Edit: for similar reasons to blog./login./support. etc. (just read other comments)

Congratulations for using example.com as it is meant to be used.

Well, that would have been helpful when I announced http://www.browser-details.com on HN - it allows you to reserve a subdomain and it never even occurred to me that I'd have to restrict them (apart from the obvious regex).

So a thoughtful HNer taught me a lesson and reserved "www". Took me a second to figure out why the site didn't behave as expected...

A popular MS Exchange cloud provider is http://webmail.domainlocalhost.com

Seriously. domainlocalhost.com.

The article looks great and makes many good points, but I'll pick on one: why disallow upper case letters from usernames?

Email addresses and domain names are case-ignoring so you should never allow usernames that differ only in case. Allowing only lower case is an easy way to do this.

The username part of an email address can actually be case sensitive, and this has been known to cause problems with some systems (e.g. https://airmail.tenderapp.com/help/discussions/287/113-case-...).

So instead of converting to lowercase, store them with case preserved but do a case insensitive uniqueness check (and probably allow any case for login).

or just force all lowercase and keep the support burden lower and save yourself a ton of trouble when dealing with foreign systems. Add a rule on incoming e-mail to convert all addresses for the local domain to lowercase to complete the package.

It probably depends on whether we're talking about making your own users, like the original link, or allowing users to interface with other systems, like entering an email address.

Yes, this seems to be the right behavior for case-insensitive things like DNS names as well. If a user inputs one, preserve the case when you store it, but do case-insensitive comparisons.

Yes, and its a pain in the butt error to track down. I was helping a friend with an old postfix / cyrus server with some custom software and case sensitivity was the final cause of bad mail delivery. Gotta love the combo of a bad config and an old mainframe app sending in all uppercase.

The local part of an email address is not required to be case-insensitive, except for the Postmaster address. RFC 822: "The domain-dependent string is uninterpreted, except by the final sub-domain; the rest of the mail service merely transmits it as a literal string."

However, there are too many services smashing the case of the local part to either lower or upper case that case-sensitive names have become nigh impossible to use.

Probably to avoid that if i have the singold user,someone takes the Singold user to impersonate me, just my guess

helpdesk is a pretty good choice to reserve just to keep people from doing some foolish things.

Just compiled the list and added a few others:

https://zimbatm.github.io/hostnames-and-usernames-to-reserve...

Feel free to use for your next PaaS !

I have handled this by only allowing more-than-one-word names to be use as subdomains, and made a slug out out of it, like so:

My Name => my-name.site.com

Is there any gotcha's here for me?

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