Strange lookup error

Hi all,

we've got here a little problem with resolving single domains. Two examples:

   ~# host www.oas.com
   www.oas.com is an alias for www.lb.oas.com.
   www.lb.oas.com has address 200.230.27.19
   ;; connection timed out; no servers could be reached

Or:

   ~# host www.lchclearnet.com
   www.lchclearnet.com is an alias for www.wip.lch.com.
   www.wip.lch.com has address 195.246.229.8
   ;; connection timed out; no servers could be reached

Any idea why we get an ip but the lookup itself fails?

Infos about our environment:

- Ubuntu 12.04 LTS
- Unbound v1.4.16-1
- Squid Proxy

If we try to access these domains through the proxy we get an dns error.

Thanks
Mathias

host is doing lookups for A, AAAA and MX. In the case of a CNAME answer to the A or AAAA queries with no additional-section answers for the CNAME RDATA, I believe host will do additional lookups.

If you want to nail this down, I suggest using dig and specifying the unbound server you suspect has problems explicitly.

Joe

Hi Mathias,

Hi all,

we've got here a little problem with resolving single domains. Two
examples:

~# host www.oas.com www.oas.com is an alias for www.lb.oas.com.
www.lb.oas.com has address 200.230.27.19 ;; connection timed out;
no servers could be reached ;; connection timed out; no servers
could be reached

Or:

~# host www.lchclearnet.com www.lchclearnet.com is an alias for
www.wip.lch.com. www.wip.lch.com has address 195.246.229.8 ;;
connection timed out; no servers could be reached

Any idea why we get an ip but the lookup itself fails?

The second and third lines in host are for the ipv6 address (AAAA
record) and the mail server (MX record). These fail with a timeout.
It is likely that the authority server for these domains does not
respond to AAAA and MX records and unbound copies this to you. If the
authority for these domains answers for AAAA and MX, even if that is
an empty packet without an answer, then you would not get a timeout here.

Infos about our environment:

- Ubuntu 12.04 LTS - Unbound v1.4.16-1 - Squid Proxy

If we try to access these domains through the proxy we get an dns
error.

It should be able to get the ipv4 address, not sure why it fails.

Best regards,
   Wouter

So I guess squid is doing AAAA lookups. I will check this...

Thanks
Mathias