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Re: What does this message mean?
On Sat, Dec 02, 2000 at 12:02:19AM +0200, Matti Aarnio wrote:
> It depends ... I used to get those too, not anymore.
> (And no, it isn't WKS related. See man-page of 'smtp' about WKS.)
Does anything these days rely on WKS? I saw one single WKS on a real
DNS record all my life ...
> Over past 3-4 weeks I have had these bounces only when
> - somebody is just changeing DNS zone datasets, and/or
> - MX defined target system does not have A-record
> (They are very rare now. 0-1 per week.)
>
> The system is somewhat sloppy here, it uses getaddrinfo(), which
> like gethostbyname() resolves text representation of addresses
> and CNAME redirection of DNS lookups.
>
> The DNS specification says that the MX value must be hostname, and it
> must have an address, specifically CNAME is not valid target for MX.
And nevertheless not an uncommon configuration ...
> If you have a system with its local getaddrinfo(), do try to check
> if it *really* works, or does it fail wrong way in case of timeouts
> on the lookups ? (Linux glibc 2.1 fails ... 2.2 is propably ok,
> not sure of other versions.)
>
> cd transports/smtp; make;
> ./getmxrr-test timeout-mx.zmailer.org
>
> That should give "temporary failure in name resolution",
> glibc 2.1 gives ... Odd, now I can't check that, where
> are my glibc 2.1 machines ... hmm...
>
> Anyway, it was something else than "temporary" error.
This is on the particular RH 6.2 / glibc 2.1.3 system:
[ralf@lappi ralf]$ /usr/lib/zmailer/getmxrr-test timeout-mx.zmailer.org
DNS lookup reply: len=163 rcode=0 qdcount=1 ancount=1 nscount=2 arcount=2 RD=1 TC=0 AA=1 QR=1 RA=1
-> (3600s) MX[0] pref=0 host=timeout-zone.zmailer.org
MX lookup lacked ADDITIONAL SECTION Address for entry: MX 0 timeout-zone.zmailer.org
mx[0] mxtype=--(0) host='timeout-zone.zmailer.org'
getaddrinfo('timeout-zone.zmailer.org','0') (PF_INET) -> r=-2 (Name or service not known), ai=(nil)
getmxrr('timeout-mx.zmailer.org') -> nmx=1, maxpref=66000, realname=''
getmxrr() rc=69 EX_UNAVAILABLE; mxcount=1
getaddrinfo('timeout-mx.zmailer.org','smtp') -> r=-2 (Name or service not known), ai=(nil)
[ralf@lappi ralf]$
Which should be the erroneous behavour you're describing.
> For that reason the configuration system has option:
> --with-ipv6-replacement-libc
Thanks, will try. What has this option to do with ipv6 btw? The particular
problem which I've reported did happen in an ipv4 only environment.
Ralf