Skip site navigation (1)Skip section navigation (2)
Date:      Sat, 27 Apr 2002 21:36:01 +0400
From:      Anton Shcherbinin <useperl@fastmail.fm>
To:        freebsd-questions@freebsd.org
Subject:   1 minute delay while connecting to any host
Message-ID:  <743669500.20020427213601@fastmail.fm>

next in thread | raw e-mail | index | archive | help
This is my 1st post to this list, and I am completely new to FreeBSD. If
I  had better ask such questions anywhere else, please tell me the right
place for this.

I  installed  FreeBSD  4.5 Release. When my host is trying to connect to
any  other  host  specified  by  name, I experience a huge (1.5 minutes)
delay before the hosts are connected. For example, suppose I want to get
http://yahoo.com/ page. I write:

$ telnet yahoo.com 80

At  the  same time (actually, a bit earlier), I wrote at another console
as root:

# tcpdump -n

And here is tcpdump's output (a bit edited for clarity):

18:37:51.501962 my_host.1055 > our_DNS_server.53:  4486+ AAAA? yahoo.com. (27)
18:37:56.512212 my_host.1056 > our_DNS_server.53:  4486+ AAAA? yahoo.com. (27)
18:38:06.522353 my_host.1057 > our_DNS_server.53:  4486+ AAAA? yahoo.com. (27)
18:38:26.532655 my_host.1058 > our_DNS_server.53:  4486+ AAAA? yahoo.com. (27)
18:39:06.543281 my_host.1059 > our_DNS_server.53:  4487+ A? yahoo.com. (27)
18:39:06.683069 our_DNS_server.53 > my_host.1059:  4487* 2/5/5 A 66.218.71.113, (238)
18:39:06.683609 my_host.1028 > yahoo.com.80: S 2162865409:2162865409(0) win 65535 <mss 1460,nop,wscale 1,nop,nop,timestamp 579069 0> (DF) [tos 0x10]
18:39:06.909922 yahoo.com.80 > my_host.1028: S 2552035614:2552035614(0) ack 2162865410 win 65535 <mss 1460,nop,wscale 1,nop,nop,timestamp 66944899 579069>
18:39:06.909984 my_host.1028 > yahoo.com.80: . ack 1 win 33304 <nop,nop,timestamp 579091 66944899> (DF) [tos 0x10]

That  is, my host tries to resolve yahoo.com at our DNS server, *but* it
looks  for 'AAAA' RR, and not 'A'. It gets no reply, and in 5 seconds it
retries  the  query (again, 'AAAA' RR). No reply again, it retries in 10
seconds,  then  again  in  20  seconds.  No  reply  within  40  seconds.
*FINALLY*,  my  host  asks  DNS server for 'A' RR for yahoo.com . And no
wonder that in several milliseconds DNS server tells my host yahoo.com's
IP  address.  Then,  within  several milliseconds, my host and yahoo.com
become TCP-connected.

As  you  can see, I had to waste 5+10+20+40==75 seconds watching my host
try to find nonexistent AAAA resource record. And things are the same if
I try to send mail or to connect to ftp site or whatever else.

What have I done wrong? What should I do? Thanks a lot for any ideas.

I  general,  what  are AAAA records? RFC1034/1035 say nothing about such
RR. What TFM should I read about them?

-- 
Anton


To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-questions" in the body of the message




Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?743669500.20020427213601>