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First of all, www.nasa.gov is a CNAME: $ host www.nasa.gov www.nasa.gov is an alias for www.nasa.gov.speedera.net. www.nasa.gov.speedera.net is an alias
by mikebabineau 14y ago
First of all, www.nasa.gov is a CNAME:
$ host www.nasa.gov
www.nasa.gov is an alias for www.nasa.gov.speedera.net.
www.nasa.gov.speedera.net is an alias for www.nasa.gov.edgesuite.net.
www.nasa.gov.edgesuite.net is an alias for a1718.dscg.akamai.net.
a1718.dscg.akamai.net has address 96.17.148.50
a1718.dscg.akamai.net has address 96.17.148.40
a1718.dscg.akamai.net has IPv6 address 2001:559:0:301::6011:6d11
a1718.dscg.akamai.net has IPv6 address 2001:559:0:301::6011:6d38
CNAMEs have special usage restrictions. Specifically, "CNAMEs must have no other resource records of other types (MX, A etc) as specified by RFC 1034 section 3.6.2 and RFC 1912 section 2.4." [http://www.dnsuniversity.com/cname.html http://www.dnsuniversity.com/cname.html]
nasa.gov has MX records associated with it:
$ dig nasa.gov MX
; <<>> DiG 9.7.3-P3 <<>> nasa.gov MX
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 48927
;; flags: qr rd ra; QUERY: 1, ANSWER: 6, AUTHORITY: 0, ADDITIONAL: 1
;; QUESTION SECTION:
;nasa.gov. IN MX
;; ANSWER SECTION:
nasa.gov. 293 IN MX 10 ndjsnpf01.ndc.nasa.gov.
nasa.gov. 293 IN MX 10 ndjsnpf02.ndc.nasa.gov.
nasa.gov. 293 IN MX 10 ndjsnpf03.ndc.nasa.gov.
nasa.gov. 293 IN MX 10 ndmsnpf01.ndc.nasa.gov.
nasa.gov. 293 IN MX 10 ndmsnpf02.ndc.nasa.gov.
nasa.gov. 293 IN MX 10 ndmsnpf03.ndc.nasa.gov.
;; ADDITIONAL SECTION:
ndmsnpf02.ndc.nasa.gov. 3 IN A 198.117.0.122
;; Query time: 27 msec
;; SERVER: 192.168.1.1#53(192.168.1.1)
;; WHEN: Wed Aug 8 15:04:31 2012
;; MSG SIZE rcvd: 202
To handle the redirection of nasa.gov to www.nasa.gov, they would need one or more nasa.gov A records that each point to a single IP address. These addresses would have HTTP servers that listen on ports 80 and 443 and redirect to www.nasa.gov. And this must be done in a highly-available way.
This infrastructure would be distinct from their existing web infrastructure (which appears to be Akamai-fronted).
So while yes, it's not the most difficult thing in the world to set up, it's not as simple as a DNS configuration change. Given NASA's strained budget and most browsers' handling of failed DNS lookups (automatically link/redirect to www.<domain>), is it really worthwhile? NASA thinks not.