4 ms·

The case in an email address does matter. Look it up.

by sandov 9y ago

spc476 9y ago
RFC-5322 (the current standard for Internet Message Formats) in section 3.4.1 states, "... how address is used and how messages are transported to a particular host is covered in separate documents, such as [RFC5321]." RFC-5321 states in section 2.3.11: ''The standard mailbox naming convention is defined to be "local-part@domain"; contemporary usage permits a much broader set of applications than simple "user names". Consequently, and due to a long history of problems when intermediate hosts have attempted to optimize transport by modifying them, the local-part MUST be interpreted and assigned semantics only by the host specified in the domain part of the address.' Furthermore, it states in section 2.4: 'The local-part of a mailbox MUST BE treated as case sensitive. Therefore, SMTP implementations MUST take care to preserve the case of mailbox local-parts. In particular, for some hosts, the user "smith" is different from the user "Smith". However, exploiting the case sensitivity of mailbox local-parts impedes interoperability and is discouraged. Mailbox domains follow normal DNS rules and are hence not case sensitive.' While you are pedantically correct, to me that reads, "don't try to change the case of the local portion of email addresses and apply no meaning to it." In other words, treat it "as-is" and assume nothing about it.
ksk 9y ago
Where does it matter? Can you give an example?
- sandov 9y ago
  If I send an email to John@company.com instead of john@company.com and the server of company.com is configured to be case sensitive, then john will never see my email.
  - Too 9y ago
    It is allowed to matter per the rfc. However I believe 99% of all mail servers in the world are configured to make it non case sensitive.
    - sandov 9y ago
      >It is allowed to matter And we don't know when it will matter and when it won't matter, therefore we have to assume that it does matter unless we are sure it doesn't for our specific case.
  - ksk 9y ago
    I see, so not relevant in the real world. Thanks!
    - dang 9y ago
      Please don't be rude on HN. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
      - ksk 9y ago
        I wasn't trying to be. I was mildly annoyed that this person was being needlessly pendantic about an irrelevant point that doesn't matter in any way whatsoever in the real world. They failed to give an example that matters.

The case in an email address does matter. Look it up.

by sandov 9y ago

The case in an email address does matter. Look it up.

RFC-5322 (the current standard for Internet Message Formats) in section 3.4.1 states, "... how address is used and how messages are transported to a particular host is covered in separate documents, such as [RFC5321]." RFC-5321 states in section 2.3.11: ''The standard mailbox naming convention is defined to be "local-part@domain"; contemporary usage permits a much broader set of applications than simple "user names". Consequently, and due to a long history of problems when intermediate hosts have attempted to optimize transport by modifying them, the local-part MUST be interpreted and assigned semantics only by the host specified in the domain part of the address.' Furthermore, it states in section 2.4: 'The local-part of a mailbox MUST BE treated as case sensitive. Therefore, SMTP implementations MUST take care to preserve the case of mailbox local-parts. In particular, for some hosts, the user "smith" is different from the user "Smith". However, exploiting the case sensitivity of mailbox local-parts impedes interoperability and is discouraged. Mailbox domains follow normal DNS rules and are hence not case sensitive.' While you are pedantically correct, to me that reads, "don't try to change the case of the local portion of email addresses and apply no meaning to it." In other words, treat it "as-is" and assume nothing about it.

ksk 9y ago

Where does it matter? Can you give an example?

sandov 9y ago
If I send an email to John@company.com instead of john@company.com and the server of company.com is configured to be case sensitive, then john will never see my email.
- Too 9y ago
  It is allowed to matter per the rfc. However I believe 99% of all mail servers in the world are configured to make it non case sensitive.
  - sandov 9y ago
    >It is allowed to matter And we don't know when it will matter and when it won't matter, therefore we have to assume that it does matter unless we are sure it doesn't for our specific case.
- ksk 9y ago
  I see, so not relevant in the real world. Thanks!
  - dang 9y ago
    Please don't be rude on HN. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
    - ksk 9y ago
      I wasn't trying to be. I was mildly annoyed that this person was being needlessly pendantic about an irrelevant point that doesn't matter in any way whatsoever in the real world. They failed to give an example that matters.