nanog mailing list archives

Re: ttl for ns


From: "Stephen J. Wilcox" <steve () telecomplete co uk>
Date: Fri, 13 Aug 2004 08:10:20 +0100 (BST)


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.

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).

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

Steve


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




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