Re: Occasional spurious ERR_DNS FAIL?

From: Jonathan Larmour <JLarmour@dont-contact.us>
Date: Mon, 23 Jun 1997 12:44:21 +0100

Some more info - I think I've found the problem. Here is an extract from
cache.log with debugging set to "ALL,1 4,1 14,9". The entries of interest
involve www.fastcompany.com, although there are other requests going on at
the same time.

Firstly, it shows the name being retrieved from the ipcache correctly. Then
note that it is released. Then it gets another request, followed by the
ERR_DNS_FAIL. Note the ipcache doesn't even try to use a dnsserver. Then
later on, we get another request which generates the correct response, i.e.
a MISS followed by a request to a dnsserver.

So I suspect there is something in the ipcache code which fails if a record
is released at just the wrong time. I think this is the limit to my
squid-hacking ability right now, so over to someone else!

Jonathan L.

97/06/23 12:12:14| ipcache_nbgethostbyname: FD 17: Name 'www.fastcompany.com'.
97/06/23 12:12:14| ipcache_nbgethostbyname: HIT for 'www.fastcompany.com'
97/06/23 12:12:14| ipcache_gethostbyname: 'www.fastcompany.com', flags=1
97/06/23 12:12:15| ipcache_nbgethostbyname: FD 20: Name 'www.blackwell.co.uk'.
97/06/23 12:12:15| ipcache_nbgethostbyname: HIT for 'www.blackwell.co.uk'
97/06/23 12:12:15| ipcache_gethostbyname: 'www.blackwell.co.uk', flags=1
97/06/23 12:12:16| ipcache_release: Released IP cached record for
'www.fastcompany.com'.
97/06/23 12:12:16| ipcache_release: Released IP cached record for
'www.dra.nl'.
97/06/23 12:12:16| ipcache_release: Released IP cached record for
'www.excite.com'.
97/06/23 12:12:16| ipcache_purgelru: ipcache_count: 8
97/06/23 12:12:16| LRU candidates : 8
97/06/23 12:12:16| high W mark : 972
97/06/23 12:12:16| low W mark : 921
97/06/23 12:12:16| not pending : 8
97/06/23 12:12:16| removed : 3
97/06/23 12:12:16| ipcache_gethostbyname: 'www.fastcompany.com', flags=0
97/06/23 12:12:16| ERR_DNS_FAIL:
http://www.fastcompany.com/community/leadership.html
97/06/23 12:12:16| dnsserver message: (null)
97/06/23 12:12:17| ipcache_gethostbyname: 'www.blackwell.co.uk', flags=0
97/06/23 12:12:17| ipcache_nbgethostbyname: FD 17: Name 'www.blackwell.co.uk'.
97/06/23 12:12:17| ipcache_nbgethostbyname: HIT for 'www.blackwell.co.uk'
97/06/23 12:12:17| ipcache_gethostbyname: 'www.blackwell.co.uk', flags=1
97/06/23 12:12:23| ipcache_nbgethostbyname: FD 22: Name 'www.fastcompany.com'.
97/06/23 12:12:23| ipcache_nbgethostbyname: MISS for 'www.fastcompany.com'
97/06/23 12:12:23| ipcache_add_to_hash: name <www.fastcompany.com>
97/06/23 12:12:23| ipcache_dnsDispatch: Request sent to DNS server #1.
97/06/23 12:12:23| ipcache_dnsHandleRead: Result from DNS ID 1 (109 bytes)
97/06/23 12:12:23| ipcache_parsebuffer: parsing:
$name www.fastcompany.com
$h_name www.fastcompany.com
$h_len 4
$ipcount 1
206.137.222.136
$aliascount 0
$end
97/06/23 12:12:23| ipcache_gethostbyname: 'www.fastcompany.com', flags=1
97/06/23 12:12:25| ipcache_gethostbyname: 'www.fastcompany.com', flags=0
97/06/23 12:12:25| ipcache_nbgethostbyname: FD 23: Name 'www.fastcompany.com'.
97/06/23 12:12:25| ipcache_nbgethostbyname: HIT for 'www.fastcompany.com'
97/06/23 12:12:25| ipcache_gethostbyname: 'www.fastcompany.com', flags=1

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Received on Mon Jun 23 1997 - 04:54:55 MDT

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