nanog mailing list archives

Re: ttl for ns


From: William Allen Simpson <wsimpson () greendragon com>
Date: Fri, 13 Aug 2004 13:46:18 -0400


"Stephen J. Wilcox" wrote:

On Thu, 12 Aug 2004, William Allen Simpson wrote:

I remain unenlightened.  Should it be 2 days?  Or 1 hour?  And why the
inconsistent results?  Obsolete root glue records?

I think your first answer is from the .com gtlds which use a 2 day ttl, the
second is from vix.com's nameservers which uses 1 hour ttl for all records.

That's a possibility, but when I checked @a.gtld-servers.net, 

;; ANSWER SECTION:
vix.net.                2D IN NS        ns1.pingmagic.com.
vix.net.                2D IN NS        ns2.pingmagic.com.

;; AUTHORITY SECTION:
vix.net.                2D IN NS        ns1.pingmagic.com.
vix.net.                2D IN NS        ns2.pingmagic.com.

;; ADDITIONAL SECTION:
ns1.pingmagic.com.      2D IN A         202.140.169.216
ns2.pingmagic.com.      2D IN A         143.89.51.48


So, A: 2 days
    ?, recursed: 2 days, 2nd set of servers
    direct: 1 hour, 3rd set of servers 


I dont know about best practice but I dont see any reason why your ns records
should be any different from the rest of your zone for which use a value which
suits you and your need to make changes (if these are your network a/ptrs
something at least 24 hours would be fine).

But that's the "thinking locally, acting globally" we're talking about 
in the earlier thread.



Having the NS records with explicitly smaller ttl wouldnt as i see it help as
any change in nameservers as made with the registry would take the time of the
registry plus the gtlds to become effective

Yes, and the registries would seem to be using 2 days.  However, for our 
domain(s) we get the same servers @a, just with longer NS times.


A simple dig yields:

;; ANSWER SECTION:
vix.com.                2D IN NS        ns-ext.vix.com.
vix.com.                2D IN NS        ns1.gnac.com.

;; AUTHORITY SECTION:
vix.com.                2D IN NS        ns1.gnac.com.
vix.com.                2D IN NS        ns-ext.vix.com.


But a dig directly to the ns1.gnac.com or ns-ext.vix.com server yields:

;; ANSWER SECTION:
vix.com.                1H IN NS        ns.lah1.vix.com.
vix.com.                1H IN NS        ns.sql1.vix.com.
vix.com.                1H IN NS        ns-ext.isc.org.
vix.com.                1H IN MX        10 sa.vix.com.
vix.com.                1H IN MX        20 fh.vix.com.
vix.com.                1H IN TXT       "$Id: vix.com,v 1.190 2004/08/12 19:06:05 vixie Exp $"
vix.com.                1H IN A         204.152.188.231
vix.com.                1H IN SOA       ns.lah1.vix.com. hostmaster.vix.com. (
                                        2004081201      ; serial
                                        1H              ; refresh
                                        30M             ; retry
                                        1W              ; expiry
                                        1H )            ; minimum


;; AUTHORITY SECTION:
vix.com.                1H IN NS        ns.lah1.vix.com.
vix.com.                1H IN NS        ns.sql1.vix.com.
vix.com.                1H IN NS        ns-ext.isc.org.

;; ADDITIONAL SECTION:
ns.lah1.vix.com.        1H IN A         204.152.188.234
ns.lah1.vix.com.        1H IN AAAA      2001:4f8:2::9
ns.sql1.vix.com.        1H IN A         204.152.184.135
ns.sql1.vix.com.        1H IN AAAA      2001:4f8:3::9
ns-ext.isc.org.         1H IN AAAA      2001:4f8:0:2::13
ns-ext.isc.org.         1H IN A         204.152.184.64
sa.vix.com.             1H IN A         204.152.187.1
sa.vix.com.             1H IN AAAA      2001:4f8:3:bb::1
-- 
William Allen Simpson
    Key fingerprint =  17 40 5E 67 15 6F 31 26  DD 0D B9 9B 6A 15 2C 32


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