Comment 27 for bug 1003842
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| Simon Kelley (simon-thekelleys) wrote Re: Precise NM with "dns=dnsmasq" breaks systems with non-equivalent upstream nameservers | #27 |
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73416ba
(Get the code!)
> Simon, your suggestion (call it "#18") differs from the suggestion in #17 in two ways. First, #18 sends the first-received reply back
> to the client without waiting for the results of comparison with other results whereas #17 does wait. Second, #18 switches to
> strict-order mode when *any* difference is found, whereas #17 proposed only looking for a particular pattern, that being: a
> NODATA/NXDOMAIN is received from a nameserver that is not listed first and an earlier-listed nameserver does return an address > within the standard libc timeout period. In #17's defence... in #17 the client only has to wait for a reply in the case of a
> NODATA/NXDOMAIN from a non-first nameserver; the client does get the desired address from the earlier-listed nameserver if
> there is one --- even the first time; and dnsmasq only drops into strict-order mode under the circumstances when it is necessary for > it to do so such that clients get needed addresses. There is no point, for example, in dropping into strict-order mode if it's the first > nameserver returning NXDOMAIN and a later-listed nameserver returning an address!
> What do you think about the possibility of implementing such ideas?
I think that both are implementable. I worry that #17 will make (real) NXDOMAIN/NODATA replies much slower, since there at least two round-trips, and possibly a timeout, if a server never replies.
Cheers,
Simon.