On Jun 29, 8:24 pm, Neil W Rickert <rickert...@cs.niu.edu> wrote:
> silent...@gmail.com writes:
> >I want to gather some statistics on TTL of certain NS records. When
> >I'm using 'dig' command (e.g. 'dig com. NS') several times I'm getting
> >cached decreasing TTL values. I've tried to clear the local DNS cache
> >with 'lookupd -flushcache', but it did not . Is there is a way to
> >get an original TTL for a given domain name?
>
> Do the lookup at the authoritative server for the record you are
> requesting.
>
> I'll use your email domain "googlegroups.com" as an example.
>
> % dig googlegroups.com
> ;; ANSWER SECTION:
> googlegroups.com. 3520 IN A 64.233.161.104
> googlegroups.com. 3520 IN A 72.14.209.104
>
> ;; AUTHORITY SECTION:
> googlegroups.com. 345520 IN NS ns3.google.com.
> googlegroups.com. 345520 IN NS ns4.google.com.
> googlegroups.com. 345520 IN NS ns1.google.com.
> googlegroups.com. 345520 IN NS ns2.google.com.
>
> This tells me that ns1.google.com is one of the authoritative
> servers for the domain.
>
> % dig @ns1.google.com. googlegroups.com
>
> ;; ANSWER SECTION:
> googlegroups.com. 3600 IN A 72.14.209.104
> googlegroups.com. 3600 IN A 64.233.161.104
>
> ;; AUTHORITY SECTION:
> googlegroups.com. 345600 IN NS ns1.google.com.
> googlegroups.com. 345600 IN NS ns2.google.com.
> googlegroups.com. 345600 IN NS ns3.google.com.
> googlegroups.com. 345600 IN NS ns4.google.com.
>
> This time I got a full TTL."googlegroups.com" as an example.
>
> % dig googlegroups.com
>
> ;; ANSWER SECTION:
> googlegroups.com. 3520 IN A 64.233.161.104
> googlegroups.com. 3520 IN A 72.14.209.104
>
> ;; AUTHORITY SECTION:
> googlegroups.com. 345520 IN NS ns3.google.com.
> googlegroups.com. 345520 IN NS ns4.google.com.
> googlegroups.com. 345520 IN NS ns1.google.com.
> googlegroups.com. 345520 IN NS ns2.google.com.
>
> This tells me that ns1.google.com is one of the authoritative
> servers for the domain.
>
> % dig @ns1.google.com. googlegroups.com
>
> ;; ANSWER SECTION:
> googlegroups.com. 3600 IN A 72.14.209.104
> googlegroups.com. 3600 IN A 64.233.161.104
>
> ;; AUTHORITY SECTION:
> googlegroups.com. 345600 IN NS ns1.google.com.
> googlegroups.com. 345600 IN NS ns2.google.com.
> googlegroups.com. 345600 IN NS ns3.google.com.
> googlegroups.com. 345600 IN NS ns4.google.com.
>
> This time I got a full TTL.
>
> This won't always work (some servers are improperly configure, or
> maybe a firewall prevents you contacting anything but the company
> DNS server).

Thanks a lot! That is what I needed!

Sergei