Plus a + sign on subdomain names

Question

example: hello + all.domain.com works with chrome / firefox. this is not with ie / safari.

I believe there is no workaround for this, right? thanks

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I add that using urlencode "works": the urencoded url works like ie / safari, but not chrome / firefox. However, it cannot use 2 URLs for the same staff.

Answer 1

The plus sign is not permitted in a valid domain name. From RFC952:

A "name" (network, host, gateway or domain name) is a text string up to 24 characters taken from the alphabet (AZ), numbers (0-9), minus sign (-) and period (.). Please note that periods are only allowed when they are used to distinguish between domain name component names.

Answer 2

The definition of host names can be found in RFC 952 and updated by RFC 1152 to allow longer host names (24 → 63).

Even with IDN (Wikipedia), the main restrictions on valid RFC 952 characters still exist, as there is (a fix):

• The "name" (network, host, gateway or domain name) is a text string up to 24 63 characters taken from the alphabet (AZ), numbers (0-9), minus sign (-) and period (.).

In IDN, Unicode characters are converted to an allowed character set with Punycode, RFC 3492 . However, ASCII characters (0 to 127 decimal places) are not punished, so the + character (43 decimal places) will remain as it is and therefore will be invalid.