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Email Address Length FAQ

24 points by nreece 17y ago

die_sekte 17y ago
Wouldn't the shortest possible Email address be 3 characters long, as in "a@b", where b is a TLD with a MX record, or did I failed to understand something critical?
- ars 17y ago
  You are correct. Although I don't think there are any TLD's with one letter. Sean Hastings <sean@ai> seems to be real, and ai has an MX record.
  - wizard_2 17y ago
    .ai seems to be a "personal TLD". Most of the websites I've found on the tld (www.ai and nic.ai) are written in first person. The registrar (same person?) takes 3 months to approve accounts after charges before giving you the domain, dns changes are made on weekends, and 2nd level domains (ie hn.ai) are reserved for residents and local companies. I don't have a problem with any of that. I'm just curious how you find yourself in charge of such a setup.
    - die_sekte 17y ago
      It's the TLD of Anguilla, and Anguilla is quite small (population of 13000, area just over 100 square kilometers), so most likely the internet of Anguilla is maintained by just a few persons whose first priority isn't the TLD and the domains in it. Personal TLDs don't exist (at least as far as I know). Some registrars are just tiny, AdamsNames for example which maintains .TC, .VG and .GD.
  - die_sekte 17y ago
    Couldn't find that Email address listed anywhere. Do you have some further information?
akkartik 17y ago
Isn't @a.gg (nothing before @) valid as an email address according to the RFC? That was my conclusion last time I parsed it..
niyazpk 17y ago
[edit: Looks like my view is just plain wrong. Skip this and directly read the replies] IMHO email address fields need not be 254 characters in length. Something like 64 is perfectly defendable I think. Why would a person sign-up with an email address of 200+ characters if he is not looking for a buffer overflow? Why would a sane person even bother to have such a long email address? How much time would he take to type that? He would have tried the email id on many other websites and some of them should have rejected it. So the person obviously does have a shorter version of his email address for those sites. How would a person fill in the emial address in a paper form where there is something like 30 fields for the email address? I'd say 64 is enough. Anything above is just weird. I can do away with those two users who have such long ids.
- prodigal_erik 17y ago
  How do you defend deliberately making something fail, when there's no benefit whatsoever? A uuid is 32 characters all by itself, and you can't get much shorter without having to start managing the way they're allocated. Not all addresses represent people.
- callahad 17y ago
  What would you gain from limiting it to 64 characters, versus complying with the RFC?
  - yhuiopkjui 17y ago
    Remember the days of 640Kb of ram and 360k disks? What did you lose by making your database not fit on a disk because you allowed 256chars for an email address and 32768 for a surname?
    - callahad 17y ago
      That's actually addressed by the original post: The memory used by a VARCHAR or VARCHAR2 data type is dependent on the actual size of the contents, not the maximum size specified. For example, one million email addresses defined using VARCHAR(255) will only take up approximately 23MB, not 255MB.
deleted 17y ago
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24 points by nreece 17y ago

Wouldn't the shortest possible Email address be 3 characters long, as in "a@b", where b is a TLD with a MX record, or did I failed to understand something critical?

ars 17y ago
You are correct. Although I don't think there are any TLD's with one letter. Sean Hastings <sean@ai> seems to be real, and ai has an MX record.
- wizard_2 17y ago
  .ai seems to be a "personal TLD". Most of the websites I've found on the tld (www.ai and nic.ai) are written in first person. The registrar (same person?) takes 3 months to approve accounts after charges before giving you the domain, dns changes are made on weekends, and 2nd level domains (ie hn.ai) are reserved for residents and local companies. I don't have a problem with any of that. I'm just curious how you find yourself in charge of such a setup.
  - die_sekte 17y ago
    It's the TLD of Anguilla, and Anguilla is quite small (population of 13000, area just over 100 square kilometers), so most likely the internet of Anguilla is maintained by just a few persons whose first priority isn't the TLD and the domains in it. Personal TLDs don't exist (at least as far as I know). Some registrars are just tiny, AdamsNames for example which maintains .TC, .VG and .GD.
- die_sekte 17y ago
  Couldn't find that Email address listed anywhere. Do you have some further information?

akkartik 17y ago

Isn't @a.gg (nothing before @) valid as an email address according to the RFC? That was my conclusion last time I parsed it..

niyazpk 17y ago

[edit: Looks like my view is just plain wrong. Skip this and directly read the replies] IMHO email address fields need not be 254 characters in length. Something like 64 is perfectly defendable I think. Why would a person sign-up with an email address of 200+ characters if he is not looking for a buffer overflow? Why would a sane person even bother to have such a long email address? How much time would he take to type that? He would have tried the email id on many other websites and some of them should have rejected it. So the person obviously does have a shorter version of his email address for those sites. How would a person fill in the emial address in a paper form where there is something like 30 fields for the email address? I'd say 64 is enough. Anything above is just weird. I can do away with those two users who have such long ids.

prodigal_erik 17y ago
How do you defend deliberately making something fail, when there's no benefit whatsoever? A uuid is 32 characters all by itself, and you can't get much shorter without having to start managing the way they're allocated. Not all addresses represent people.
callahad 17y ago
What would you gain from limiting it to 64 characters, versus complying with the RFC?
- yhuiopkjui 17y ago
  Remember the days of 640Kb of ram and 360k disks? What did you lose by making your database not fit on a disk because you allowed 256chars for an email address and 32768 for a surname?
  - callahad 17y ago
    That's actually addressed by the original post: The memory used by a VARCHAR or VARCHAR2 data type is dependent on the actual size of the contents, not the maximum size specified. For example, one million email addresses defined using VARCHAR(255) will only take up approximately 23MB, not 255MB.

deleted 17y ago

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