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

[Rob Crittenden]

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

-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/x-pkcs7-signature
Size: 3245 bytes
Desc: S/MIME Cryptographic Signature
URL: <http://listman.redhat.com/archives/freeipa-devel/attachments/20080328/71cd58a6/attachment.bin>