Last week, I was trying to access a web page on my daughter’s school web site, www.austinisd.org, and the page would not come up. At first, I thought it might be a server load issue, since everyone is gearing up to go back to school.
To investigate, I opened a shell window and tried to
ping the site with command,
ping www.austinisd.org. Usually, when you ping a site, such as
ping google.com the command will return with the web site’s IP address.
$ ping www.google.com PING www.google.com (18.104.22.168): 56 data bytes 64 bytes from 22.214.171.124: icmp_seq=0 ttl=59 time=9.359 ms 64 bytes from 126.96.36.199: icmp_seq=1 ttl=59 time=9.313 ms 64 bytes from 188.8.131.52: icmp_seq=2 ttl=59 time=9.307 ms 64 bytes from 184.108.40.206: icmp_seq=3 ttl=59 time=9.090 ms
With those results I knew a few things. The domain www.google.com would resolve to the IP address 220.127.116.11 and this server was responding back to my ping requests.
When I tried to ping the school’s web server, I never did get an IP address from the DNS server. Instead I received the following error message.
$ ping www.austinisd.org ping: cannot resolve www.austinisd.org: Unknown host
My solution was to change my DNS resolver setting on my Mac to point to a different DNS server. Google runs a DNS resolver at 18.104.22.168 and I added this to my settings and Bam! I can now connect to www.austinisd.org.
$ ping www.austinisd.org PING austinisd.org (22.214.171.124): 56 data bytes 64 bytes from 126.96.36.199: icmp_seq=0 ttl=54 time=37.234 ms 64 bytes from 188.8.131.52: icmp_seq=1 ttl=54 time=35.116 ms 64 bytes from 184.108.40.206: icmp_seq=2 ttl=54 time=35.513 ms