HP gethostbyaddr errors
Mark.Andrews at nominum.com
Mark.Andrews at nominum.com
Mon Apr 17 03:45:27 UTC 2000
> All,
>
> We have a customer who is having trouble with BIND 8.2.2-P5 on HP-UX 11.
>
> They use router management software (Spectrum on Solaris) that maps the
> network topology and uses reverse resolution to determine the device name of
> the router. Because they are monitoring multiple interfaces on the router,
> the name in the management software will change regularly. To circumvent
> this, we have created the reverse resolution entries to all resolve to the
> same name ie:
>
> Forward Resolution entries:
>
> interfacea 129600 IN A 10.13.255.5
> interfaceb 129600 IN A 10.13.128.1
> interfacea 129600 IN A 10.13.130.1
>
> Reverse Resolution entries: (13.10.in-addr.arpa)
>
> 5.255 129600 IN PTR interfacea.ssi.govt.nz.
> 1.128 129600 IN PTR interfacea.ssi.govt.nz.
> 1.130 129600 IN PTR interfacea.ssi.govt.nz.
>
> They have a different management product - HP Network Node Manager running
> on HP-UX 11. For some reason, this host seems to want to verify that the A
> record matches the PTR. We get a message in syslog:
> gethostbyaddr : timcr100.ssi.govt.nz != 10.213.130.1
This message indicates that when gethostbyaddr did a reverse
lookup on 10.213.130.1 it found the name was timcr100.ssi.govt.nz.
It then performed a forward lookup on timcr100.ssi.govt.nz
and didn't find 10.213.130.1 as a valid address for
timcr100.ssi.govt.nz.
This could be due to a error in the DNS or to a limitation in
gethostbyname (called by gethostbyaddr) which limits the number
of addresses to 35.
Mark
>
> As this box is managing over 2,000 addresses, it is doing a lot of name
> resolution and filling up the syslog on the host very quickly. Note that
> the management works OK. The customer called HP to get them to resolve the
> problem and HP are saying that the DNS configuration of mismatched A and PTR
> records is "broken". The engineer has quoted from page 64 of O'Reilly DNS &
> BIND:
>
> "To state as a general rule: if a host is multihomed create an address
> record for each alias unique to one address. Create a CNAME record for
> each alias common to all the addresses"
>
> Of course, this method doesn't provide for a single name per device on the
> Spectrum management server.
>
> My questions:
> 1. Is the described method considered to be a broken implementation? I
> haven't seen any explicit statements in the RFC's that state that the PTR
> MUST match the A record.
> 2. Any suggestions on how to work around this other than force a change
> with HP?
>
> TIA
>
> J.
>
> James Hall-Kenney
> Sytec Resources Limited
>
>
>
>
>
--
Mark Andrews, Nominum Inc. / Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: Mark.Andrews at nominum.com
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