Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!cis.ohio-state.edu!karl_kleinpaste From: karl_kleinpaste@cis.ohio-state.edu Newsgroups: comp.mail.misc Subject: Re: Which headers may Sendmail re-write? Message-ID: Date: 6 Dec 90 22:11:55 GMT References: <208@frcs.UUCP> <1990Dec6.042257.9620@blilly.UUCP> Sender: news@tut.cis.ohio-state.edu Organization: OSU Lines: 44 bruce@balilly.uucp writes: > To: user@toaster To: toaster!user@gatebox > From: me@tinytoy From: tinytoy!me@gatebox The applicable RFC's (including 822) require that addresses on the internet must be in domain form (not ! paths), and that fully-qualified domains be used. To clarify that just a bit, the RFCs require that addresses on the Internet be FQDNs _if_ they are going outside their domain of origin. Abbreviations within a domain are fine. RFC822 section 6.2.2 page 29: Since any number of levels is possible within the domain hierarchy, specification of a fully qualified address can become inconvenient. This standard permits abbreviated domain specification... When a message crosses a domain boundary, all addresses must be specified in the full format, ending with the top-level name-domain in the right-most field. It is the responsibility of mail forwarding services to ensure that addresses conform with this requirement. In the case of abbreviated addresses, the relaying service must make the necessary expansions... The "gatebox" in question is doing exactly the right thing if it is making addresses palatable to things outside your domain. If it's doing it for destinations within your domain, it's harmless but not especially useful. If your site inflicts "user@tinytoy" on my sendmail, I'm going to finish the job of address-breaking that your site started: It's going to be rewritten as user@cis.ohio-state.edu. This rewrite does the Right Thing in the usual case where Joe Random writes mail to, e.g., jane@apple. I have to interpret OneWordHostNames within the context of cis.ohio-state.edu, a host apple.cis.ohio-state.edu exists, and we hide hostnames anyway, so I rewrite all OWHNs as cis.ohio-state.edu. Since a recipient here of address "user@tinytoy" couldn't have replied directly to it anyway, I figure it serves 'em right if they have to hunt through Received: headers for the real information they needed. I post an explanatory "mail/news/finger glitches and solutions" to a local newsgroup periodically so that the users know what's what. --karl Brought to you by Super Global Mega Corp .com