Date: Sun, 28 Apr 2002 23:17:38 +0400 From: Anton Shcherbinin <useperl@fastmail.fm> To: Greg 'groggy' Lehey <grog@FreeBSD.org> Cc: freebsd-questions@freebsd.org Subject: IPv6: how can I get rid of it? Message-ID: <1411696390.20020428231738@fastmail.fm> In-Reply-To: <20020428104538.B83112@wantadilla.lemis.com> References: <743669500.20020427213601@fastmail.fm> <LPBBIGIAAKKEOEJOLEGOOEPMCOAA.barbish@a1poweruser.com> <20020428104538.B83112@wantadilla.lemis.com>
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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? 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 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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