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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Weird DNS issues for domains
On Thu, 29 Sep 2005, John Dupuy wrote: > If you are talking about strictly http, then you are probably right. If you > are hosting any email, then this isn't the case. A live DNS but dead mail > server will cause your mail to queue up for a later resend on the originating > mail servers. A dead DNS will cause the mail to bounce as undeliverable. If a mail server is bouncing immediately on a DNS SERVFAIL (which is what you'll get when a remote DNS server is down), then that mail server is badly broken and will break quite a bit during tier1 failure situations. Failure to resolve != resolves to NXDOMAIN/empty. A failure to resolve (SERVFAIL) should result in the same queueing behavior that the remote SMTP server uses for failure to establish a TCP connection. -- -- Todd Vierling <[email protected]> <[email protected]> <[email protected]>
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