[Freeipa-devel] [PATCH] ipv6 compatible way to check the hostname

[Simo Sorce]

Rob Crittenden wrote:
> Simo Sorce wrote:
>> This change checks the machine can resolve address using nsswitch host 
>> name resolution, this means we are also checking that /etc/hosts is 
>> not broken.
>>
>> It uses IPv6 aware system functions, so this should make it also IPv6 
>> compatible.
>>
>> It does not force to have a DNS set up correctly, but that's 
>> intentional as we might want to install DNS as part of the 
>> installation (--setup-bind) and checking DNS before installing it 
>> wouldn't really work :-)
>>
>> It still do try to check the DNS but currently it just exists silently 
>> if DNS is not configured. I am not sure how to raise a warning without 
>> throwing an exception that would make the install script abort in this 
>> case.
>>
>> It does error out if DNS is setup incorrectly.
>>
> 
> +
> +    rev = None
> +    for rsn in rs:
> +        if rsn.dns_type == dnsclient.DNS_T_A:
> +            rev = rsn
> +            break
> +
> +    if rev == None:
> +        raise RuntimeError("Cannot find PTR record for %s" % addr)
> +
> +    reverse = rev.rdata.ptrdname
> 
> Should you be looking for DNS_T_PTR here instead? If you have an A 
> record you won't have a ptrdname.
> 
> You need to add a try/except around socket.getaddrinfo() to catch errors 
> if the hostname isn't found so a more useful error message can be 
> returned than 'Name or service not known'
> 
> gethostbyaddr may need a try/except around it too.
> 
> rob
> 



Good points, new patch attached.

Simo.
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