[wp-hackers] New Codex page on WordPress Optimization
les at lcb.me.uk
Wed Sep 5 07:04:31 GMT 2007
> -----Original Message-----
> From: wp-hackers-bounces at lists.automattic.com [mailto:wp-hackers-
> bounces at lists.automattic.com] On Behalf Of Kimmo Suominen
> Sent: 05 September 2007 07:21
> To: wp-hackers at lists.automattic.com
> Subject: Re: [wp-hackers] New Codex page on WordPress Optimization
> On Tue, Sep 04, 2007 at 08:55:17PM +0100, Les Bessant wrote:
> > Normal practice is to have at least two name servers, which should be
> > physically separate networks. If your name servers are on the same
> > as the application server, then in the event of a loss of
> connectivity, your
> > domain drops off the internet in the worst possible way - rather than
> > getting error messages indicating that the server is inaccessible,
> > will get "no such domain" errors.
> > That's bad for web servers. If you're running email on the domain,
> > potentially catastrophic - instead of messages being queued for
> > when the server comes back, they'll bounce with extreme force...
> That's not true. You can only get "no such domain" if you get an
> NXDOMAIN answer from a name server. When none of the name servers can
> be reached, you get a temporary failure (typically SERVFAIL or no
> at all). Your website cannot be reached, but mail will be queued.
> If all your services are on a single network, it doesn't really buy
> you much to have your name servers distributed outside it. During an
> outage, in the best case the visitor still gets a good DNS answer, but
> won't be able to reach the site. In the case of mail, the message
> gets queued.
> Best regards,
> + Kimmo
That's interesting, but doesn't conform to my own experience of domains set
up that way. I have seen mail bounce when the name servers for a domain are
not contactable. With no MX records available, most mail servers I'm aware
of will not queue mail but will return it to sender. Mail gets queued for
redelivery attempts when the server knows where to send it - if there is no
known destination it's less likely to be queued.
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