Each dns record has a time to live field in it. This is specified by the administrator of the dns master zone server. This is not you. The dns server will automatically expire cached entries. This is why when you change your domain name to a new server (ip address) you have an up to 4 day delay called propagation delay as the caching dns servers expire your domain name and get the new entry. By the way, this can be avoided by setting your domain name ttl to 5 minutes for a few days, then switching the ip address and setting the ttl back to a normal 24 hours or so. Propagation delay is then reduced to 5 minutes and less. This is a trick I learned from my new isp, to whom I just switched: Eschelon.
www.microsoft.com: 6951 seconds or about 2 hours. Note each time dig is run the ttl field will have decreased. This is because my caching server is counting it down. $ dig www.microsoft.com ; <<>> DiG 9.2.1 <<>> www.microsoft.com ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 65228 ;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;www.microsoft.com. IN A ;; ANSWER SECTION: www.microsoft.com. 6951 IN CNAME www.microsoft.akadns.net. www.microsoft.akadns.net. 51 IN A 207.46.249.190 ;; Query time: 6 msec ;; SERVER: 127.0.0.1#53(127.0.0.1) ;; WHEN: Sun Dec 8 15:33:52 2002 ;; MSG SIZE rcvd: 89 On Sun, Dec 08, 2002 at 03:14:52PM -0800, Dexter Graphic wrote: > > A DNS server running in this fashion is termed a caching dns server. > > ...This means the first lookup goes over the internet connection, all > > subsequent lookups are made either on the local machine or over a lan > > depending on the setup. > > When, if ever, does the DNS server check to see if an address has changed? > > _______________________________________________ > Eug-LUG mailing list > [EMAIL PROTECTED] > http://mailman.efn.org/cgi-bin/listinfo/eug-lug > _______________________________________________ Eug-LUG mailing list [EMAIL PROTECTED] http://mailman.efn.org/cgi-bin/listinfo/eug-lug
