4 ms·

"Email is Easy" email address quiz

47 points by samwho 1y ago

tyilo 1y ago
Last week I created a script for finding which TLD's have MX records. Result: cf: ["mail.intnet.cf."] gp: ["ns1.nic.gp."] gt: ["aspmx.l.google.com.", "alt1.aspmx.l.google.com.", "alt2.aspmx.l.google.com.", "aspmx2.googlemail.com.", "aspmx4.googlemail.com.", "aspmx5.googlemail.com."] hr: ["alpha.carnet.hr."] km: ["mail1.comorestelecom.km."] mq: ["mx1-mq.mediaserv.net."] mr: ["mail.nic.mr."] tt: ["ASPMX.L.GOOGLE.COM.", "ALT1.ASPMX.L.GOOGLE.COM."] ua: ["mr.kolo.net."] ws: ["mail.worldsite.ws."] موريتانيا: ["mail.nic.mr."] عرب: ["your-dns-needs-immediate-attention.عرب."] PS: Only http://uz/ seems to have a "working" HTTP server, returning the 500 status code.
vthriller 1y ago
I'm not sure if I'd count examples with spaces and comments towards valid emails, because one could argue these are not part of the address, they're email header syntax details. Like, sure, FWS from RFC can be used somewhere in the address, but it can also be in any other header. Also, CFWS and whatnot are going to get stripped anyway by the time you'd have to deal with SMTP (see Forward-path in RFC 5321, which doesn't allow `(nonsense in parentheses)`), so I don't think they should be considered part of the valid address anyway.
docsaintly 1y ago
I think using example.com is a bit of a trick question. It is known as an example domain which is invalid for all purposes, except of course for serving as an example. :) https://www.iana.org/help/example-domains https://www.iana.org/help/example-domains
- wredcoll 1y ago
  I've actually been wondering for a while if example.com is a valid example email address.
  - mdaniel 1y ago
    Well, "valid," yes, but "deliverable" thankfully, no $ dig MX example.com. ;; ANSWER SECTION: example.com. 3600 IN MX 0 . Almost certainly the same for its .org .net and .example friends. There were some other TLDs that were designed for use in documentation, but I don't have the RFC in front of me right now to cite them
    - SoftTalker 1y ago
      Some of the other examples which are "technically valid but obsolete" I would consider safe to call invalid for practical purposes.
      - samwho 1y ago
        Yeah, I almost put a disclaimer at the end saying that while these examples are valid according to the spec, that has no bearing on whether they’re usable in practice. Email is the Wild West.
- olddustytrail 1y ago
  Exactly. Not valid because it can't be routed.
- TMWNN 1y ago
  Yes. If I'd known that other questions would also use example.com, I would have answered the first question correctly.
- paulnpace 1y ago
  An explanation of the use of example.com would have informed users that addresses should be evaluated as such, otherwise, AFAICT, all of the examples provided are invalid.
sour-taste 1y ago
Love it. Minor but question 8 should maybe be 'trailing' instead of 'tailing'?
- samwho 1y ago
  Good eyes! Code is at https://github.com/samwho/e-mail.wtf https://github.com/samwho/e-mail.wtf if you’d like to open a PR
rpgraham84 1y ago
would be nice if what valid means was clearly defined before the test. what the rfc's regex allows is probably the least useful way to think about email validation.
- mdaniel 1y ago
  I see some of the sibling comments seem to imply that "valid" means that it's deliverable at that moment in time, which would make producing a quiz like this some nonsense because then they'd have to actually register xn--tp8h as a domain, and create an MX record for it
- samwho 1y ago
  I do have a short sentence on the homepage saying I used https://github.com/jackbearheart/email-addresses https://github.com/jackbearheart/email-addresses as the validator for the examples. It could be more clearly defined, though.
xigoi 1y ago
I scored 17/21 on https://e-mail.wtf https://e-mail.wtf and all I got was this lousy text to share on social media.
mdaniel 1y ago
As far as I know, that emoji question due to the same reason IDN is allowed in URLs, and they even went as far as their own RFC for it https://datatracker.ietf.org/doc/html/rfc6530 https://datatracker.ietf.org/doc/html/rfc6530 (very similar to the 6532 cited repeatedly, but more important(?) because every system in between the sender and recipient needs to know about hops, whereas the recipient is the terminal node's problem The LHS is, as far as I know, because the LHS of _all_ email addresses is "if it's deliverable", modulo the rest of the call-outs from the rest of the quiz
stavros 1y ago
This is fun, but it feels suspiciously close to my old presentation about the exact same thing: https://www.youtube.com/watch?v=xxX81WmXjPg https://www.youtube.com/watch?v=xxX81WmXjPg Maybe it's just a coincidence, but a shoutout would have been nice if not.
- Dilettante_ 1y ago
  Same guy made https://jsdate.wtf https://jsdate.wtf, also posted to HN, and also containing material from someone else's talk I'm pretty sure. Edit: I was wrong!
  - samwho 1y ago
    Similar to this I got my examples for jsdate.wtf through reading the v8 date parsing code and experimentation. Wasn’t aware there was a talk with similar examples for JS dates, would be interested to see it.
    - Dilettante_ 1y ago
      My bad, I was thinking about a much older talk[1], maybe something about the theme activated the same neurons. Sorry for making an accusation like that for what turns out was no reason. [1]https://www.destroyallsoftware.com/talks/wat https://www.destroyallsoftware.com/talks/wat
      - samwho 1y ago
        It’s okay <3 it doesn’t surprise me that both of these topics have been covered before, and both are fairly small input spaces so there’s bound to be similarities or overlap. I do love Gary’s “wat” talk, it was certainly part of the inspiration to make these.
- samwho 1y ago
  Coincidence. I hadn’t seen this. I got my examples mostly from looking through https://github.com/jackbearheart/email-addresses/blob/master/test/tests.json https://github.com/jackbearheart/email-addresses/blob/master... and reading the EBNF in RFC 5322. Will watch your video!
zvr 1y ago
There should have been questions without "@" as well...
- samwho 1y ago
  Are there valid emails without an @? I’m very vaguely aware of bang paths but didn’t want to include them because they’re a bit too esoteric.
  - fanf2 1y ago
    Canonically postmaster is valid without a domain in SMTP. Traditionally mail messages can be composed to local users without writing domains in their addressses, and the message submission service will add domains where necessary.
  - zvr 1y ago
    Well, of course, in a multi-user system you can send an email to "user". Typically used for system processes to email "root" back in the day, or "postmaster" or other system accounts, as well. Bang paths host!user or even host1!host2!user were used in the past, and I think they are still supported by most MTAs. They are definitely valid syntax for email addresses. I mean, if you're talking about quotes and parentheses, ...
tmdetect 1y ago
Funny. I definitely knew there were some unique characteristics, but this took it to a new level.
- samwho 1y ago
  Thank you <3 which one got the biggest laugh?
  - nocoiner 1y ago
    I chortled audibly at the goatse one.
fanf2 1y ago
Some notes: * Single-label domains are problematic in several ways. Traditionally they are used as local abbreviations on the assumption that TLDs can’t be mail domains – tho that’s false, because several ccTLDs have had MX records at one time or another. Still, mail software can vary in whether it might treat single-label domains as abbreviations or TLDs or both. And there’s the historical anomaly that RFC 2821’s syntax disallows single-label domains; this was a drafting mistake not an intentional change. * Spaces around local parts are valid or not depending on which spec you are following, so question 7 is badly framed. You need to be clear whether you are parsing a mail address as in the SMTP envelope, or an address and display name as in a message header. * Similarly, comments are not valid in SMTP so the questions about comments are also poorly framed. * And the syntax of domain literals / address literals is specified by SMTP, so question 16 and 18 are based on not reading enough of the RFCs.
jayski 1y ago
15/21. I was expecting a question about simple%example1.com@example2.com. which I remember was a useful trick when I worked as a sendmail admin in the early 2000s.

47 points by samwho 1y ago

Last week I created a script for finding which TLD's have MX records. Result: cf: ["mail.intnet.cf."] gp: ["ns1.nic.gp."] gt: ["aspmx.l.google.com.", "alt1.aspmx.l.google.com.", "alt2.aspmx.l.google.com.", "aspmx2.googlemail.com.", "aspmx4.googlemail.com.", "aspmx5.googlemail.com."] hr: ["alpha.carnet.hr."] km: ["mail1.comorestelecom.km."] mq: ["mx1-mq.mediaserv.net."] mr: ["mail.nic.mr."] tt: ["ASPMX.L.GOOGLE.COM.", "ALT1.ASPMX.L.GOOGLE.COM."] ua: ["mr.kolo.net."] ws: ["mail.worldsite.ws."] موريتانيا: ["mail.nic.mr."] عرب: ["your-dns-needs-immediate-attention.عرب."] PS: Only http://uz/ seems to have a "working" HTTP server, returning the 500 status code.

vthriller 1y ago

I'm not sure if I'd count examples with spaces and comments towards valid emails, because one could argue these are not part of the address, they're email header syntax details. Like, sure, FWS from RFC can be used somewhere in the address, but it can also be in any other header. Also, CFWS and whatnot are going to get stripped anyway by the time you'd have to deal with SMTP (see Forward-path in RFC 5321, which doesn't allow `(nonsense in parentheses)`), so I don't think they should be considered part of the valid address anyway.

docsaintly 1y ago

I think using example.com is a bit of a trick question. It is known as an example domain which is invalid for all purposes, except of course for serving as an example. :) https://www.iana.org/help/example-domains https://www.iana.org/help/example-domains

wredcoll 1y ago
I've actually been wondering for a while if example.com is a valid example email address.
- mdaniel 1y ago
  Well, "valid," yes, but "deliverable" thankfully, no $ dig MX example.com. ;; ANSWER SECTION: example.com. 3600 IN MX 0 . Almost certainly the same for its .org .net and .example friends. There were some other TLDs that were designed for use in documentation, but I don't have the RFC in front of me right now to cite them
  - SoftTalker 1y ago
    Some of the other examples which are "technically valid but obsolete" I would consider safe to call invalid for practical purposes.
    - samwho 1y ago
      Yeah, I almost put a disclaimer at the end saying that while these examples are valid according to the spec, that has no bearing on whether they’re usable in practice. Email is the Wild West.
olddustytrail 1y ago
Exactly. Not valid because it can't be routed.
TMWNN 1y ago
Yes. If I'd known that other questions would also use example.com, I would have answered the first question correctly.
paulnpace 1y ago
An explanation of the use of example.com would have informed users that addresses should be evaluated as such, otherwise, AFAICT, all of the examples provided are invalid.

sour-taste 1y ago

Love it. Minor but question 8 should maybe be 'trailing' instead of 'tailing'?

samwho 1y ago
Good eyes! Code is at https://github.com/samwho/e-mail.wtf https://github.com/samwho/e-mail.wtf if you’d like to open a PR

rpgraham84 1y ago

would be nice if what valid means was clearly defined before the test. what the rfc's regex allows is probably the least useful way to think about email validation.

mdaniel 1y ago
I see some of the sibling comments seem to imply that "valid" means that it's deliverable at that moment in time, which would make producing a quiz like this some nonsense because then they'd have to actually register xn--tp8h as a domain, and create an MX record for it
samwho 1y ago
I do have a short sentence on the homepage saying I used https://github.com/jackbearheart/email-addresses https://github.com/jackbearheart/email-addresses as the validator for the examples. It could be more clearly defined, though.

xigoi 1y ago

I scored 17/21 on https://e-mail.wtf https://e-mail.wtf and all I got was this lousy text to share on social media.

mdaniel 1y ago

As far as I know, that emoji question due to the same reason IDN is allowed in URLs, and they even went as far as their own RFC for it https://datatracker.ietf.org/doc/html/rfc6530 https://datatracker.ietf.org/doc/html/rfc6530 (very similar to the 6532 cited repeatedly, but more important(?) because every system in between the sender and recipient needs to know about hops, whereas the recipient is the terminal node's problem The LHS is, as far as I know, because the LHS of _all_ email addresses is "if it's deliverable", modulo the rest of the call-outs from the rest of the quiz

stavros 1y ago

This is fun, but it feels suspiciously close to my old presentation about the exact same thing: https://www.youtube.com/watch?v=xxX81WmXjPg https://www.youtube.com/watch?v=xxX81WmXjPg Maybe it's just a coincidence, but a shoutout would have been nice if not.

Dilettante_ 1y ago
Same guy made https://jsdate.wtf https://jsdate.wtf, also posted to HN, and also containing material from someone else's talk I'm pretty sure. Edit: I was wrong!
- samwho 1y ago
  Similar to this I got my examples for jsdate.wtf through reading the v8 date parsing code and experimentation. Wasn’t aware there was a talk with similar examples for JS dates, would be interested to see it.
  - Dilettante_ 1y ago
    My bad, I was thinking about a much older talk[1], maybe something about the theme activated the same neurons. Sorry for making an accusation like that for what turns out was no reason. [1]https://www.destroyallsoftware.com/talks/wat https://www.destroyallsoftware.com/talks/wat
    - samwho 1y ago
      It’s okay <3 it doesn’t surprise me that both of these topics have been covered before, and both are fairly small input spaces so there’s bound to be similarities or overlap. I do love Gary’s “wat” talk, it was certainly part of the inspiration to make these.
samwho 1y ago
Coincidence. I hadn’t seen this. I got my examples mostly from looking through https://github.com/jackbearheart/email-addresses/blob/master/test/tests.json https://github.com/jackbearheart/email-addresses/blob/master... and reading the EBNF in RFC 5322. Will watch your video!

zvr 1y ago

There should have been questions without "@" as well...

samwho 1y ago
Are there valid emails without an @? I’m very vaguely aware of bang paths but didn’t want to include them because they’re a bit too esoteric.
- fanf2 1y ago
  Canonically postmaster is valid without a domain in SMTP. Traditionally mail messages can be composed to local users without writing domains in their addressses, and the message submission service will add domains where necessary.
- zvr 1y ago
  Well, of course, in a multi-user system you can send an email to "user". Typically used for system processes to email "root" back in the day, or "postmaster" or other system accounts, as well. Bang paths host!user or even host1!host2!user were used in the past, and I think they are still supported by most MTAs. They are definitely valid syntax for email addresses. I mean, if you're talking about quotes and parentheses, ...

tmdetect 1y ago

Funny. I definitely knew there were some unique characteristics, but this took it to a new level.

samwho 1y ago
Thank you <3 which one got the biggest laugh?
- nocoiner 1y ago
  I chortled audibly at the goatse one.

fanf2 1y ago

Some notes: * Single-label domains are problematic in several ways. Traditionally they are used as local abbreviations on the assumption that TLDs can’t be mail domains – tho that’s false, because several ccTLDs have had MX records at one time or another. Still, mail software can vary in whether it might treat single-label domains as abbreviations or TLDs or both. And there’s the historical anomaly that RFC 2821’s syntax disallows single-label domains; this was a drafting mistake not an intentional change. * Spaces around local parts are valid or not depending on which spec you are following, so question 7 is badly framed. You need to be clear whether you are parsing a mail address as in the SMTP envelope, or an address and display name as in a message header. * Similarly, comments are not valid in SMTP so the questions about comments are also poorly framed. * And the syntax of domain literals / address literals is specified by SMTP, so question 16 and 18 are based on not reading enough of the RFCs.

jayski 1y ago

15/21. I was expecting a question about simple%example1.com@example2.com. which I remember was a useful trick when I worked as a sendmail admin in the early 2000s.