From owner-freebsd-security Sat Feb 1 19:55:45 2003 Delivered-To: freebsd-security@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id DFFB237B401 for ; Sat, 1 Feb 2003 19:55:42 -0800 (PST) Received: from gw.nectar.cc (gw.nectar.cc [208.42.49.153]) by mx1.FreeBSD.org (Postfix) with ESMTP id 15DEA43E4A for ; Sat, 1 Feb 2003 19:55:42 -0800 (PST) (envelope-from nectar@celabo.org) Received: from opus.celabo.org (opus.celabo.org [10.0.1.111]) by gw.nectar.cc (Postfix) with ESMTP id 384662D; Sat, 1 Feb 2003 21:55:41 -0600 (CST) Received: by opus.celabo.org (Postfix, from userid 1001) id 1BEA45A22; Sat, 1 Feb 2003 21:53:11 -0600 (CST) Date: Sat, 1 Feb 2003 21:53:10 -0600 From: "Jacques A. Vidrine" To: Michael Bryan Cc: Ralph Dratman , freebsd-security@FreeBSD.ORG Subject: Re: SSHD suddenly takes SIX MINUTES to authenticate Message-ID: <20030202035310.GA14640@opus.celabo.org> Mail-Followup-To: "Jacques A. Vidrine" , Michael Bryan , Ralph Dratman , freebsd-security@FreeBSD.ORG References: <3E3B1D71.21CFBD42@ursine.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3E3B1D71.21CFBD42@ursine.com> X-Url: http://www.celabo.org/ User-Agent: Mutt/1.5.1i-ja.1 Sender: owner-freebsd-security@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Fri, Jan 31, 2003 at 05:05:53PM -0800, Michael Bryan wrote: > There was a bug in older versions of OpenSSH, with symptoms exactly > matching what you're seeing. For every connection, sshd would do > a DNS lookup of the special krb5-realm domain. (It did this even > if Kerberos support was disabled.) However, it would start out by > looking for krb5-realm.yoursubdomain.yourdomain.com, which is fine. > Then it would start stepping up the tree, checking for krb5-realm.yourdomain.com, > then krb5-realm.com. If the nameservers setup to host krb5-realm.com > stop responding to requests, then these DNS lookups take a long time, > waiting to eventually timeout. Actually, that was a Heimdal (not OpenSSH) mis-feature. See src/crypto/heimdal/lib/krb5/get_host_realm.c:dns_find_realm for the current state of affairs. Cheers, -- Jacques A. Vidrine http://www.celabo.org/ NTT/Verio SME . FreeBSD UNIX . Heimdal Kerberos jvidrine@verio.net . nectar@FreeBSD.org . nectar@kth.se To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message