Problems with bind9 caching too long
kcd at daimlerchrysler.com
Sat Mar 12 00:37:56 UTC 2005
No, that's not a BIND bug. You've left the old version of the zone
running on ns1.pbi.net and ns2.pbi.net, and they'll keep on giving out
the stale NS records in response to queries. Other caching nameservers
such as aludra.usc.edu which had the NS records cached from prior to the
switchover will keep on using those nameservers to resolve nakos.net
names, and therefore keep seeing regurgitations of the stale NS records,
and the cycle will repeat until those caching nameservers are restarted
or those particular records in their caches expire or are purged out, or
until the pbi.net nameservers stop answering with stale NS records for
the zone (i.e. the zone is removed from them or is replaced by a more
Phil Dibowitz wrote:
>I've been having problems with Bind 9 caching too long. I finally have a nice
>concrete example, and I can't find a good reason, so I'm coming here.
>nakos.net's whois record was changed over a month ago to change is NS servers
>from ns1.pbi.net. and ns2.pbi.net. to ns1.iswest.net. and ns2.iswest.net.
>[phil at metallica tmp]$ dig @aludra.usc.edu nakos.net
>; <<>> DiG 9.2.4rc6 <<>> @aludra.usc.edu nakos.net
>;; global options: printcmd
>;; Got answer:
>;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 58363
>;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 0
>;; QUESTION SECTION:
>;nakos.net. IN A
>;; ANSWER SECTION:
>nakos.net. 6709 IN A 188.8.131.52
>;; AUTHORITY SECTION:
>nakos.net. 172309 IN NS ns1.pbi.net.
>nakos.net. 172309 IN NS ns2.pbi.net.
>;; Query time: 1 msec
>;; SERVER: 184.108.40.206#53(aludra.usc.edu)
>;; WHEN: Fri Mar 11 11:42:19 2005
>;; MSG SIZE rcvd: 83
>[phil at metallica tmp]$
>But if I do a +trace, I get the proper information.
>net. 172800 IN NS H.GTLD-SERVERS.net.
>net. 172800 IN NS I.GTLD-SERVERS.net.
>net. 172800 IN NS J.GTLD-SERVERS.net.
>;; Received 512 bytes from 220.127.116.11#53(E.ROOT-SERVERS.NET) in 10 ms
>nakos.net. 172800 IN NS ns1.iswest.net.
>nakos.net. 172800 IN NS ns2.iswest.net.
>;; Received 102 bytes from 18.104.22.168#53(K.GTLD-SERVERS.net) in 144 ms
>nakos.net. 28800 IN A 22.214.171.124
>nakos.net. 28800 IN NS ns1.iswest.net.
>nakos.net. 28800 IN NS ns2.iswest.net.
>;; Received 118 bytes from 126.96.36.199#53(ns1.iswest.net) in 4 ms
>The TTL for nakos.net from the root server is 48 hours, and this was changed
>over a month ago (or so I'm told - I don't control this domain, but I've had
>many similar reports recently).
>I don't see why the cache is living so long....
>Any help would be appreciated. Thanks.
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