pete@??? (Pete Naylor) wrote on 11.10.99 in <Pine.GSO.4.05.9910112128030.2099-100000@???>:
> On Mon, 11 Oct 1999, Peter Radcliffe wrote:
>
> > Pete Naylor <pete@???> probably said:
> > > Please explain in more detail. I fail to see how round robin DNS is
> > > related to providing multiple mail servers with any sort of failover
> > > mechanism so I have to assume that this is another case of misuse.
> >
> > The MX record for example.com points at mail.example.com.
> > mail.example.com has two A records, 10.0.0.1 and 10.0.0.2, two
> > distinct machines for failover. nscd caches mail.example.com as
> > 10.0.0.1 when someone sends mail to example.com. 10.0.0.1 goes down.
> > Mail never reaches 10.0.0.2 until the first A record times out from
> > nscd, which is a long time since nscd's default timeouts for positive
> > caching are quite high.
> >
> > This is broken.
>
> That's right - I hope nobody is silly enough to configure their DNS in the
> manner that you've just described. Really bad practice.
Um, if the described behaviour of nscd is real, then I strongly suspect it
breaks a MUST in one of the DNS RFCs (by caching only one of those two A
records).
There can really be *no* excuse for this behaviour.
MfG Kai
