From owner-freebsd-questions Wed Jan 14 06:36:30 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id GAA29275 for questions-outgoing; Wed, 14 Jan 1998 06:36:30 -0800 (PST) (envelope-from owner-freebsd-questions@FreeBSD.ORG) Received: from caladan.tdx.co.uk (caladan.tdx.co.uk [195.188.177.4]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id GAA29110 for ; Wed, 14 Jan 1998 06:35:53 -0800 (PST) (envelope-from kpielorz@tdx.co.uk) Received: from tdx.co.uk (lorca-tx.tdx.co.uk [195.188.177.242]) by caladan.tdx.co.uk (8.8.5/8.8.5) with ESMTP id OAA14279; Wed, 14 Jan 1998 14:15:50 GMT Message-ID: <34BCCE75.36A89467@tdx.co.uk> Date: Wed, 14 Jan 1998 14:40:53 +0000 From: Karl Pielorz Organization: TDX X-Mailer: Mozilla 4.04 [en] (WinNT; I) MIME-Version: 1.0 To: Steven Harris CC: questions@FreeBSD.ORG Subject: Re: Telnet and SYN problem References: <3.0.32.19980114194527.00b84744@202.139.228.50> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk It sounds like the machines your trying to contact are trying to do a reverse DNS check (common on FreeBSD where most places run a small utility called 'tcp wrappers')... This is where the server will first try to lookup your machine's IP address (reverse DNS) - then it will lookup the name that results - and make sure the IP addresses match... If they don't, or it can't - it kicks you out... (hence the delay while all the DNS lookups happen)... Check on your system (by using nslookup) that your system can resolve it's own address, and name (and that some other nameserver on the net can) - and also check with your ISP that they do provide for reverse DNS addresses for their address space... Regards, Karl Should give you ' Steven Harris wrote: > > Hi, > > We've just connected up via ISDN and it's marvellous. Unfortunatly, we > cannot talk to other freebsd server properly. I can telnet to any other > (non-freebsd) server without a problem. HTTP works, but telnet, ftp and > other TCP/IP related services seem to hang and time out. For example, if I > telnet to "www.freebsd.org" I get: > > bash# telnet www.freebsd.org > Trying 204.216.27.18... > Connected to hub.freebsd.org. > Escape character is '^]'. > Connection closed by foreign host. > > This is the same for all FreeBSD sites and FTP too. I took a look at the > netstat table on the server that I am telnetting to and get: > > tcp 0 0 playgal.telnet imageisdn.ozemai.1996 SYN_RCVD > > It sits there for about 1 minute and disconnects. Any hints or ideas would > be **GREATLY** appreciated :) > > Steve > Admin.