[squid-users] DNS not caching properly

From: Michael K Bender <benderm@dont-contact.us>
Date: Tue, 25 Sep 2001 15:37:49 -0400

I had written earlier today about a problem with an ASP page that I was having problems with. I have
discovered and remedied, somewhat, that problem. However, now I have another problem.

There is a server that I am trying to connect to: time.records.com (example)

This server name is aliased to time.card.records.com and has 3 IP addresses. Each of these three IP
addresses, also, is aliased to names (time1.card.records.com, time2, time3). If I put as my URL
time1.card.records.com the proxying works fine and I can browse through and use the ASP pages. However, if I
use time.records or time.card.records, I have problems. If I look through a snoop log of the connection
between my squid server and time.records.com I find that squid seems to randomly send packets and responses to
different time1, time2, or time3 servers. The DNS is using a round-robin system to determine which IP is
returned when a lookup is performed on time.records.com, but I thought that squid would cache the IP it
received for the positive TTL time (still default 6 hours). It appears to be performing a new DNS lookup
every time it has to send a packet to the server, and it is getting a different one, which is confusing the
ASP page.

The ASP page sends a Cache-control=private header which prevents squid from caching it. Does this also
preclude squid from caching the DNS entry? If so, is there any way to fix this problem?

Mike

-- 
*==========================================*
# Mike Bender     Marlboro System Managers #
#     benderm@sels.rsc.raytheon.com        #
#            508.490.2849                  #
*==========================================*
Received on Tue Sep 25 2001 - 13:39:52 MDT

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