Re: [squid-users] DNS double query

> On Fri, 9 Apr 2004, dtom wrote:
>
> > I am using squid-2.5.STABLE5 on Sun Solaris8. I monitored DNS query and respons by using
> > snoop command, then snoop showed DNS double query and respons every accessing to internet web site
> > through squid cache box.
>
> Probably your DNS is slower than your dns_retransmit_interval, but there
> is a number of other possibilities as well...
>
> What was the timing of the queries and responses? (first column in tcpdump
> output is time...)
>
> Regards
> Henrik

My DNS is very fast.
I got following snoop output and cache.log while accessing http://www.mail-archive.com/.
H.H.H.H is squid box IP and A.A.A.A is DNS IP.
You can see sets of double queries and responses. Query line was very quickly shown after
response line was shown.
Two "idnsRead: FD 6: received 124 bytes from A.A.A.A." are written to cache.log.
I don't want squid to query twice.

Thanks
Tomi

# snoop -r -d hme0 port 53
Using device /dev/hme (promiscuous mode)
H.H.H.H -> A.A.A.A DNS C www.mail-archive.com. Internet Addr ?
H.H.H.H -> A.A.A.A DNS C www.mail-archive.com. Internet Addr ?
A.A.A.A -> H.H.H.H DNS R www.mail-archive.com. Internet Addr 64.62.136.189
A.A.A.A -> H.H.H.H DNS R www.mail-archive.com. Internet Addr 64.62.136.189
H.H.H.H -> A.A.A.A DNS C www.mail-archive.com. Internet Addr ?
H.H.H.H -> A.A.A.A DNS C www.mail-archive.com. Internet Addr ?
A.A.A.A -> H.H.H.H DNS R www.mail-archive.com. Internet Addr 64.62.136.189
A.A.A.A -> H.H.H.H DNS R www.mail-archive.com. Internet Addr 64.62.136.189
H.H.H.H -> A.A.A.A DNS C www.mail-archive.com. Internet Addr ?
H.H.H.H -> A.A.A.A DNS C www.mail-archive.com. Internet Addr ?
A.A.A.A -> H.H.H.H DNS R www.mail-archive.com. Internet Addr 64.62.136.189
A.A.A.A -> H.H.H.H DNS R www.mail-archive.com. Internet Addr 64.62.136.189

=== cache.log ===
2004/04/09 13:47:56| aclCheck: checking 'always_direct allow EADDR'
2004/04/09 13:47:56| aclMatchAclList: checking EADDR
2004/04/09 13:47:56| aclMatchAcl: checking 'acl EADDR dst D.D.D.D/12 E.E.E.E/16'
2004/04/09 13:47:56| ipcache_gethostbyname: 'www.mail-archive.com', flags=1
2004/04/09 13:47:56| ipcache_nbgethostbyname: Name 'www.mail-archive.com'.
2004/04/09 13:47:56| ipcache_nbgethostbyname: MISS for 'www.mail-archive.com'
2004/04/09 13:47:56| idnsALookup: buf is 38 bytes for www.mail-archive.com, id = 0x18
2004/04/09 13:47:56| cbdataLock: 3d7408
2004/04/09 13:47:56| commSetSelect: FD 6 type 1
2004/04/09 13:47:56| eventAdd: Adding 'idnsCheckQueue', in 1.000000 seconds
2004/04/09 13:47:56| aclMatchAcl: Can't yet compare 'EADDR' ACL for 'www.mail-archive.com'
2004/04/09 13:47:56| aclMatchAclList: no match, returning 0
2004/04/09 13:47:56| ipcache_nbgethostbyname: Name 'www.mail-archive.com'.
2004/04/09 13:47:56| ipcache_nbgethostbyname: MISS for 'www.mail-archive.com'
2004/04/09 13:47:56| cbdataLock: 3de810
2004/04/09 13:47:56| idnsALookup: buf is 38 bytes for www.mail-archive.com, id = 0x19
2004/04/09 13:47:56| cbdataLock: 3d7448
2004/04/09 13:47:56| commSetSelect: FD 6 type 1
2004/04/09 13:47:56| cbdataUnlock: 3de470
2004/04/09 13:47:56| cbdataUnlock: 3a41b8
2004/04/09 13:47:56| cbdataFree: 3dec18
2004/04/09 13:47:56| cbdataFree: Freeing 3dec18
2004/04/09 13:47:56| cbdataUnlock: 3de470
2004/04/09 13:47:56| cbdataUnlock: 3a41b8
2004/04/09 13:47:56| cbdataFree: 3f4cc0
2004/04/09 13:47:56| cbdataFree: Freeing 3f4cc0
2004/04/09 13:47:56| cbdataUnlock: 3de470
2004/04/09 13:47:56| cbdataUnlock: 3a41b8
2004/04/09 13:47:56| cbdataFree: 3f5e40
2004/04/09 13:47:56| cbdataFree: Freeing 3f5e40
2004/04/09 13:47:56| comm_poll: 1+0 FDs ready
2004/04/09 13:47:56| idnsRead: FD 6: received 124 bytes from A.A.A.A.
2004/04/09 13:47:56| idnsGrokReply: ID 0x18, 1 answers
2004/04/09 13:47:56| cbdataValid: 3d7408
2004/04/09 13:47:56| cbdataUnlock: 3d7408
2004/04/09 13:47:56| cbdataFree: 3d7408
2004/04/09 13:47:56| cbdataFree: Freeing 3d7408
2004/04/09 13:47:56| ipcacheParse: #0 64.62.136.189
2004/04/09 13:47:56| idnsRead: FD 6: received 124 bytes from A.A.A.A.
2004/04/09 13:47:56| idnsGrokReply: ID 0x19, 1 answers
2004/04/09 13:47:56| cbdataValid: 3d7448
2004/04/09 13:47:56| cbdataUnlock: 3d7448
2004/04/09 13:47:56| cbdataFree: 3d7448
2004/04/09 13:47:56| cbdataFree: Freeing 3d7448
2004/04/09 13:47:56| ipcacheParse: #0 64.62.136.189
2004/04/09 13:47:56| cbdataValid: 3de810
2004/04/09 13:47:56| cbdataValid: 1ca1f8
2004/04/09 13:47:56| aclCheck: checking 'always_direct allow EADDR'
2004/04/09 13:47:56| aclMatchAclList: checking EADDR
2004/04/09 13:47:56| aclMatchAcl: checking 'acl EADDR dst 172.16.0.0/12 192.168.0.0/16'
2004/04/09 13:47:56| ipcache_gethostbyname: 'www.mail-archive.com', flags=1
2004/04/09 13:47:56| aclMatchIp: '64.62.136.189' NOT found
2004/04/09 13:47:56| aclMatchAclList: no match, returning 0
2004/04/09 13:47:56| cbdataUnlock: 1ca1f8
2004/04/09 13:47:56| aclCheck: NO match found, returning 0
2004/04/09 13:47:56| aclCheckCallback: answer=0
2004/04/09 13:47:56| cbdataValid: 3f4c30
2004/04/09 13:47:56| peerCheckAlwaysDirectDone: 0
2004/04/09 13:47:56| peerSelectFoo: 'GET www.mail-archive.com'
2004/04/09 13:47:56| cbdataLock: 1ca068
2004/04/09 13:47:56| cbdataLock: 3f4c30
2004/04/09 13:47:56| cbdataValid: 1ca068
2004/04/09 13:47:56| aclCheck: checking 'never_direct allow all'
2004/04/09 13:47:56| aclMatchAclList: checking all
2004/04/09 13:47:56| aclMatchAcl: checking 'acl all src 0.0.0.0/0.0.0.0'
2004/04/09 13:47:56| aclMatchIp: 'X.X.X.X' found
2004/04/09 13:47:56| aclMatchAclList: returning 1
2004/04/09 13:47:56| aclCheck: match found, returning 1
2004/04/09 13:47:56| cbdataUnlock: 1ca068
2004/04/09 13:47:56| aclCheckCallback: answer=1
2004/04/09 13:47:56| cbdataValid: 3f4c30
2004/04/09 13:47:56| peerCheckNeverDirectDone: 1
2004/04/09 13:47:56| peerSelectFoo: 'GET www.mail-archive.com'
2004/04/09 13:47:56| peerSelectFoo: direct = DIRECT_NO
2004/04/09 13:47:56| peerSelectIcpPing: http://www.mail-archive.com/squid-users@squid-cache.org/msg14387.html
2004/04/09 13:47:56| neighborsCount: 0
Received on Fri Apr 09 2004 - 00:34:52 MDT