Difference between revisions of "Network/Troubleshooting/DNS"

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m (to bypass -> for bypassing)
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We have recently experienced a number of issues with Comcast home internet not correctly handling DNS resolution for UMIACS hostnames, that can seem to be affecting connectivity to UMIACS.
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We have experienced in the past a number of issues with home internet providers not correctly handling DNS resolution for UMIACS hostnames that can seem to be affecting connectivity to UMIACS.
  
In the face of continuing disruptions of Comcast's DNS services, here are a few last-resort options for bypassing problematic DNS services...
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In the face of this, here are a few last-resort options for bypassing problematic DNS services...
  
 
===[http://en.wikipedia.org/wiki/Google_Public_DNS Google DNS]===
 
===[http://en.wikipedia.org/wiki/Google_Public_DNS Google DNS]===
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===How to change your default DNS servers===
 
===How to change your default DNS servers===
* '''Windows Vista/7:''' Under Control Panel > Network and Internet > Network and Sharing Center
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* '''Windows Vista/7/8/10:''' Under Control Panel > Network and Internet > Network and Sharing Center
 
::# Click "Change adapter settings" on the left.  
 
::# Click "Change adapter settings" on the left.  
 
::# Right click on the network adapter you're using, choose "Properties" from the context menu.
 
::# Right click on the network adapter you're using, choose "Properties" from the context menu.
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===Manual Lookup===
 
===Manual Lookup===
If you are having problems getting to UMIACS hosts you can use our name servers to resolve those specific host names then connect using the IP addresses you lookup. Our name servers are 128.8.120.19, 128.8.120.50, and 128.8.132.75 to use this information to get the ip address of the host somehost.umiacs.umd.edu you would use the command "nslookup somehost.umiacs.umd.edu 128.8.120.19", from a linux, windows or mac command prompt.
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If you are having problems getting to UMIACS hosts you can use our name servers to resolve those specific host names then connect using the IP addresses you lookup. Our name servers are 128.8.120.19, 128.8.120.50, and 128.8.132.75 to use this information to get the ip address of the host somehost.umiacs.umd.edu you would use the command "nslookup somehost.umiacs.umd.edu 128.8.120.19", from a linux, windows, or mac command prompt.

Revision as of 18:40, 31 August 2016

We have experienced in the past a number of issues with home internet providers not correctly handling DNS resolution for UMIACS hostnames that can seem to be affecting connectivity to UMIACS.

In the face of this, here are a few last-resort options for bypassing problematic DNS services...

Google DNS

IP Addresses:

  • 8.8.8.8
  • 8.8.4.4

OpenDNS

IP Addresses:

  • 208.67.222.222
  • 208.67.220.220
  • 208.67.222.220
  • 208.67.220.222

How to change your default DNS servers

  • Windows Vista/7/8/10: Under Control Panel > Network and Internet > Network and Sharing Center
  1. Click "Change adapter settings" on the left.
  2. Right click on the network adapter you're using, choose "Properties" from the context menu.
  3. Select "Internet Protocol Version 4 (TCP/IPv4)" and click on the "Properties" button.
  4. If not selected, choose "Use the following DNS server addresses:"
  5. Enter the public DNS addresses you desire to use.
  6. click OK, and close the remaining windows
  • Mac OSX: System Preferences > Network > Advanced > DNS
  • Linux: edit your /etc/resolv.conf file and change the ip addresses after "nameserver" to any of those listed above.

Manual Lookup

If you are having problems getting to UMIACS hosts you can use our name servers to resolve those specific host names then connect using the IP addresses you lookup. Our name servers are 128.8.120.19, 128.8.120.50, and 128.8.132.75 to use this information to get the ip address of the host somehost.umiacs.umd.edu you would use the command "nslookup somehost.umiacs.umd.edu 128.8.120.19", from a linux, windows, or mac command prompt.