wrl@FORD-COS2.ARPA (Bill Lewandowski) (10/24/88)
I have a Mail Adressing Question I'm sure someone out there can help me with: Where can I find an explaination for the "%" (percent) character as it is used in Internet Mail Addressing ? I have gotten out RFC-821/822/733 and I can not see where the "%" is a reserved or special character (It's not used in any examples in either document). I know it's valid for sendmail but I have not been able to find a reference yet. I'm wondering if someone can point me to a document (RFC etc) that covers the "%". Any help would be appreciated. Bill Lewandowski Ford Aerospace Corporation WRL@Ford-Cos2.arpa Colorado Springs Division (719) 594-1899
lear@NET.BIO.NET (Eliot Lear) (10/24/88)
Bill Lewandowski asks about the use of '%' in addresses. I don't remember if/when '%' was mentioned as far as the RFCs are concerned. I am fairly certain it is not listed in the RFCs you mentioned. RFC822 doesn't mention '%' so I assume it is treated as a local character. In theory, a route-addr requires a host to be registered. I am told that this is what made '%' popular. People needed ways to send mail to other networks, such as BITNET, where machines were not registered. -- Eliot Lear [lear@net.bio.net]
ron@ron.rutgers.edu (Ron Natalie) (10/24/88)
RFC 822 and SMTP and Internet mail in general doesn't know '%' from any other character. When you send mail there are essentially two significant parts. The stuff to the left of the '@' and the stuff to the right of the '@'. When you send mail to a remote machine you interpret the stuff to the right as the machine to connect to and pass to it the stuff on the left uninterpretted. Now if a host wants to use this character for some internal use (either it allows a mailbox name to contain that character, or it is used for a separater), this makes no difference to SMTP or 822. All it knows is that you care dropping mail into a mailbox whose id is the stuff to the left of the '@.' Now some machines use % as a special separator (notably older attempts at CSNET mail). They will essentially throw away the '@' and what is to the right and then turn the % into an '@' and attempt to resend the mail. Generally this was used to route mail to another host which is not really on the newtork. However, it is up to the recipient host to make this distinction, and if a host decided that % in a name means to send that mail to the lineprinter, it's free to make that interpretation. -Ron