HP gethostbyaddr errors

[Cricket Liu]

> 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
>
> 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?

You're not following the described method.  If you were, your
records would look like this:

router        129600  IN      A       10.13.255.5
router        129600  IN      A       10.13.128.1
router        129600  IN      A       10.13.130.1
interfacea        129600  IN      A       10.13.255.5
interfaceb        129600  IN      A       10.13.128.1
interfacea        129600  IN      A       10.13.130.1

cricket

Acme Byte & Wire
cricket at acmebw.com
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