Hi all,

We have a client we host a web for (blog.foobar.es). We do not manage foobar.es's DNS setup, we just told them to point blog.foobar.es to our web server's IP.

We have noticed that sometimes we cannot browse to blog.foobar.es, but we can browse to other sites on that server.

Troubleshooting a bit using host(1) yields something funny:

$ host blog.foobar.es 8.8.8.8
Using domain server:
Name: 8.8.8.8
Address: 8.8.8.8#53
Aliases: 
Host blog.foobar.es not found: 3(NXDOMAIN)

, being 8.8.8.8 one of Google's public DNS servers. However, sometimes the same server resolves the name correctly (!).

Another funny thing, is that our ISP's DNS servers sometimes say:

$ host blog.foobar.es 80.58.61.250

Using domain server:
Name: 80.58.61.250
Address: 80.58.61.250#53
Aliases: 

blog.foobar.es has address x.x.x.x
Host blog.foobar.es not found: 3(NXDOMAIN)

Which I don't really understand. I've dug around using dig(1), and have noticed they've set up a SOA record for foobar.es:

$ dig foobar.es

; <<>> DiG 9.7.0-P1 <<>> foobar.es
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 59824
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;foobar.es.         IN   A

;; AUTHORITY SECTION:
foobar.es.      86400   IN   SOA   dns1.provider.es. root.dns1.provider.es. 2011030301 86400 7200 2592000 172800

;; Query time: 78 msec
;; SERVER: 80.58.61.250#53(80.58.61.250)
;; WHEN: Thu Mar  3 16:16:19 2011
;; MSG SIZE  rcvd: 78

... which I'm completely unfamiliar with.

Ideas?

We can't really do much as we do not control DNS, but we'd like to point our clients in the right direction...