Date: Sun, 28 Apr 2002 15:27:24 -0400 (EDT) From: Peter Leftwich <Hostmaster@Video2Video.Com> To: Anton Shcherbinin <useperl@fastmail.fm> Cc: Greg 'groggy' Lehey <grog@FreeBSD.ORG>, FreeBSD LIST <FreeBSD-Questions@FreeBSD.Org> Subject: Re: IPv6: how can I get rid of it? Message-ID: <20020428152315.O49612-100000@earl-grey.cloud9.net> In-Reply-To: <1411696390.20020428231738@fastmail.fm>
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On Sun, 28 Apr 2002, Anton Shcherbinin wrote: > Sunday, April 28, 2002, 5:15:39, Greg 'groggy' Lehey wrote: > > On Saturday, 27 April 2002 at 16:32:28 -0400, Joe & Fhe Barbish wrote: > >> On Saturday, April 27, 2002 1:36 PM, Anton Shcherbinin wrote: > >>> 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 66944899579069> > >>> 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? > > They're address records for IPV6. > Thank you, Greg. It makes things much clearer. > > > So what's the problem? I really don't know. Does this only happen > > with telnet? Only with yahoo.com? > As I have already said, the same happens with any application and any > host. E. g., with ftp and ftp.freebsd.org : > 1) my host queries our DNS server for AAAA record of ftp.freebsd.org > 2) query times out in 5 secs > 3) the same query > 4) query times out in 10 secs > 5) the same query > 6) query times out in 20 secs > 7) the same query > 8) query times out in 40 secs > 9) the same query, *but* for A record; DNS server replies in some ms, > and then everything goes great, my host quickly connects > to ftp.freebsd.org:21 etc. > > How can I fix that? > The only thing I could think of is to disable IPv6 at all. But wait a > second: > > $ grep -i ipv6_enable /etc/rc* /etc/defaults/* > /etc/rc:case ${ipv6_enable} in > /etc/defaults/rc.conf:ipv6_enable="NO" # Set to YES to set up for IPv6. > > ^^^^^^^^^^^^^^^^ > Does not it mean that IPv6 is already disabled? Check in both /etc/rc.conf and /etc/defaults/rc.conf -- your /etc/rc.conf file overrides anything that is set in the /defaults/ version of the same. > On the other hand: > $ ifconfig -u > rl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 > inet 10.10.10.9 netmask 0xffffff00 broadcast 10.10.10.255 > inet6 fe80::2c0:26ff:fea5:b640%rl0 prefixlen 64 scopeid 0x1 > ether 00:c0:26:a5:b6:40 > media: Ethernet autoselect (100baseTX <full-duplex>) > status: active > lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384 > inet6 ::1 prefixlen 128 > inet6 fe80::1%lo0 prefixlen 64 scopeid 0x3 > inet 127.0.0.1 netmask 0xff000000 > > Both interfaces have IPv6 (inet6) addresses. > > I deal with IPv6 the 1st time in my life. I just understand nothing. > :-( > What should I do? I am ready to give you any additional info about my FBSD configuration. Many thanks in advance. -Anton From `man -k ipv6` ip6(4) - Internet Protocol version 6 (IPv6) ip6fw(8) - controlling utility for IPv6 firewall The online handbook probably has a good description of enabling, understanding, and disabling IPV6 (think of the IP addresses of the future as 10.3.2.1.0.100 beyond 10.3.2.1). The url is http://www.freebsd.org -- Peter Leftwich President & Founder Video2Video Services Box 13692, La Jolla, CA, 92039 USA +1-413-403-9555 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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