From owner-freebsd-questions Sat Nov 30 3:47:10 2002 Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id D77A337B401 for ; Sat, 30 Nov 2002 03:47:07 -0800 (PST) Received: from smtp.infracaninophile.co.uk (smtp.infracaninophile.co.uk [81.2.69.218]) by mx1.FreeBSD.org (Postfix) with ESMTP id A092B43E4A for ; Sat, 30 Nov 2002 03:47:06 -0800 (PST) (envelope-from m.seaman@infracaninophile.co.uk) Received: from happy-idiot-talk.infracaninophile.co.uk (localhost.infracaninophile.co.uk [IPv6:::1]) by smtp.infracaninophile.co.uk (8.12.6/8.12.6) with ESMTP id gAUBksQf083842 for ; Sat, 30 Nov 2002 11:46:54 GMT (envelope-from matthew@happy-idiot-talk.infracaninophile.co.uk) Received: (from matthew@localhost) by happy-idiot-talk.infracaninophile.co.uk (8.12.6/8.12.6/Submit) id gAUBkniY083841 for freebsd-questions@FreeBSD.ORG; Sat, 30 Nov 2002 11:46:49 GMT Date: Sat, 30 Nov 2002 11:46:49 +0000 From: Matthew Seaman To: freebsd-questions@FreeBSD.ORG Subject: Re: disable inet6? Message-ID: <20021130114649.GA11836@happy-idiot-talk.infracaninophi> Mail-Followup-To: Matthew Seaman , freebsd-questions@FreeBSD.ORG References: <20021129212359.A357-100000@13507.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20021129212359.A357-100000@13507.net> User-Agent: Mutt/1.5.1i X-Spam-Status: No, hits=-3.0 required=5.0 tests=IN_REP_TO,QUOTED_EMAIL_TEXT,REFERENCES,SPAM_PHRASE_02_03, USER_AGENT,USER_AGENT_MUTT version=2.43 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Fri, Nov 29, 2002 at 09:29:00PM -0500, alex wrote: > I have freebsd 4.7 installed... and it was working just great... till it > decided it (or me) decided to start inet6... > > here's my theory... > > got a bunch of daemons that hang on boot... and sometimes on use.. > including sendmail and my ftp server... when i send a message in pine.. it > takes about a minute to actually send... and this started happening when i > saw that inet6 showed up on the ifconfig... That sounds like DNS breakage to me. It's certainly the case that the sendmail MSP spends a lot of effort looking up the loopback address, which is ::1 for IPv6. (That is probably what's causing the delays in pine, too). There are other places where IPv6 stuff can cause the system to wait for a DNS query to time out, several of which are down to other people not running properly standards compliant software out there on the 'net. You can test how well your system can look up IPv6 addresses by: dig -x ::1 IN PTR Ideally this will return 'localhost' within a few milliseconds. Second best is a negative response (ie. no answer to be found) which will probably take a second or so to resolve. The worst case is that you get no answer at all until the resolver gives up and times out. Other than switching IPv6 off entirely, as has been suggested, you could try a few other measures to fix up various problematic areas: * Make sure that: ::1 localhost localhost.your.domain.com appears in /etc/hosts * Alternatively run named(8) locally as a caching name server --- that's essentially what the default configuration in /etc/namedb/named.conf gets you. Be sure to get the latest version of that file (1.6.2.6 in the RELENG_4 branch) with the RFC 3152 stuff in it. Remember to alter /etc/resolv.conf so that your new nameservice cache becomes your first choice server. * Modify the configuration in your sendmail configuration (both MSP and MTA flavours) to tell it only to bind to IPv4 addresses. eg: FEATURE(no_default_msa)dnl ## overridden with DAEMON_OPTIONS below DAEMON_OPTIONS(`Port=587,Name=MSA,M=E')dnl DAEMON_OPTIONS(`Name=IPv4,Family=inet')dnl in /etc/mail/`hostname`.mc, and FEATURE(`msp', `[127.0.0.1]')dnl in /etc/mail/freebsd.submit.mc * Make your ftp server bind to just the IPv4 address by commenting out the: ftp stream tcp6 nowait root /usr/libexec/ftpd ftpd -l line in /etc/inetd.conf --- send inetd a HUP signal to reload it's configuration: killall -HUP inetd You won't need *all* of these measures --- choose whatever is most suitable... Cheers, Matthew -- Dr Matthew J Seaman MA, D.Phil. 26 The Paddocks Savill Way Marlow Tel: +44 1628 476614 Bucks., SL7 1TH UK To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message