DNS questions

Prime95 · 2003-04-10, 22:23

My ISP has two DNS servers. 24.95.227.34 and 24.95.227.35.

Q1) Why has the new mersenne.org IP address propagated to the second server but not the first?

Q2) I placed the second server first in my Windows XP list of DNS servers. All works OK. Except --- once a day Windows XP reverts back to thinking mersenne.org is at 216.120.70.80. I have to switch the DNS server list and switch it back to restore the correct IP address for mersenne.org. Why is WindowsXP doing this to me?

cperciva · 2003-04-10, 22:43

Quote:

Originally Posted by Prime95

Q1) Why has the new mersenne.org IP address propagated to the second server but not the first?

Probably the first server cached the old address more recently. DNS updates don't propagate, old values die out.

Quote:

Q2) I placed the second server first in my Windows XP list of DNS servers. All works OK. Except --- once a day Windows XP reverts back to thinking mersenne.org is at 216.120.70.80. Why is WindowsXP doing this to me?

Probably the first server failed to respond to a request once, so Windows decided to switch to using the second server as primary. Which makes sense, since otherwise if the first server died, every request you ever did would have to wait for a timeout before it would be sent to the second server.

trif · 2003-04-12, 01:54

For some strange reason, the first DNS server is holding on to the old DNS information. It has a TTL of 24 hours, so it should have been cleared out long ago. All of the .org servers have the updated DNS, so the only thing I can think of is that the first DNS server is having problems querying the .org servers and is renewing the TTL on the old info. I can see that at this moment, the "bad" server is showing a TTL of just under 24 hours, so presumably it very recently queried the old nameservers for mersenne.org, when it should have queried the .org servers, gotten the new nameservers, and then queried them for the proper IP.

You can just use the "good" DNS server and eliminate the other until it gets itself fixed.

2003-04-10, 22:23	#1
Prime95 P90 years forever! Aug 2002 Yeehaw, FL 5·7·11·19 Posts	DNS questions My ISP has two DNS servers. 24.95.227.34 and 24.95.227.35. Q1) Why has the new mersenne.org IP address propagated to the second server but not the first? Q2) I placed the second server first in my Windows XP list of DNS servers. All works OK. Except --- once a day Windows XP reverts back to thinking mersenne.org is at 216.120.70.80. I have to switch the DNS server list and switch it back to restore the correct IP address for mersenne.org. Why is WindowsXP doing this to me?

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2003-04-12, 01:54	#3
trif Aug 2002 2×101 Posts	For some strange reason, the first DNS server is holding on to the old DNS information. It has a TTL of 24 hours, so it should have been cleared out long ago. All of the .org servers have the updated DNS, so the only thing I can think of is that the first DNS server is having problems querying the .org servers and is renewing the TTL on the old info. I can see that at this moment, the "bad" server is showing a TTL of just under 24 hours, so presumably it very recently queried the old nameservers for mersenne.org, when it should have queried the .org servers, gotten the new nameservers, and then queried them for the proper IP. You can just use the "good" DNS server and eliminate the other until it gets itself fixed.