Slow DNS Name Resolution When Using PPTP Connection

The information in this article applies to:

SYMPTOMS

Domain Name Service (DNS) name resolution may be slow (approximately 75 seconds) when you are using a Point-to-Point Tunneling Protocol (PPTP) connection.


CAUSE

This behavior occurs because of the order in which the DNS servers are queried. The DNS server name received from the PPTP Remote Access Services (RAS) server is added to the end of the list of DNS servers and is queried last. The default assigned DNS servers time out after you make the PPTP connection because there is no longer a valid route to them.


MORE INFORMATION

The following sample scenario demonstrates the behavior described above:

  1. You have a working Internet connection that uses DNS servers A and B.


  2. You make a PPTP connection to a remote network. A new IP address, default gateway, and DNS server C is assigned to your computer.


  3. The DNS search order becomes A, then B, then C.


  4. You try an operation that uses DNS name resolution. Your computer tries to connect to DNS server A, then tries to connect to DNS server B, and then tries to connect to DNS server C.


  5. The queries to servers A and B time out because there is no longer a valid route to them (because the default gateway has changed).


  6. Waiting for DNS servers A and B to time out causes a delay (approximately 75 seconds) before DNS server C is queried and name resolution is achieved.


NOTE: This scenario assumes that another DNS server is assigned after the PPTP connection is made. DNS queries do not work if a DNS server is not assigned after the connection is made to the remote network.

Keywords : win95 ras
Version : WINDOWS:95
Platform : WINDOWS
Issue type : kbprb
Technology :


Last Reviewed: May 26, 1999
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