Date: Wed, 14 Jan 1998 14:40:53 +0000 From: Karl Pielorz <kpielorz@tdx.co.uk> To: Steven Harris <steve@playgal.com> Cc: questions@FreeBSD.ORG Subject: Re: Telnet and SYN problem Message-ID: <34BCCE75.36A89467@tdx.co.uk> References: <3.0.32.19980114194527.00b84744@202.139.228.50>
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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.
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