cross platform telnet question

mmn mmn at inix.com
Sat Oct 21 01:56:10 PDT 2000


Thank you for the links and the info. From what's in the message I think
networking isn't properly set up on the Linux box (first time I've ever done
thing
mathisha  (mmn ;)

Chris Bopp wrote:

> Dear mmn (is that your name?):
>
> When I first saw your question, I began to write
> a response and realized that I was simply restating
> things from the following (much more authoritative)
> sources:
>
> --- There is probably enough right here
> The Linux Networking HOWTO (formerly the NET-3 HOWTO):
> http://howto.tucows.com/otherhowto/NET3-4-HOWTO
>
> --- Unless you think the Linux hardware itself is not setup:
> The Ethernet HOWTO:
> http://howto.tucows.com/LDP/HOWTO/Ethernet-HOWTO.html
>
> --- Not Linux-specific, but excellent ground-up expo
> --- and Olaf Kirsch is a god
> The Network Administrator's Guide (NAG)
> http://howto.tucows.com/LDP/LDP/nag/index.html
>
> --- Short list of big documents, including the NAG
> Page of guide links at TUCOWS:
> http://howto.tucows.com/guides.html
>
> --- Long list of pointers to specialized stuff;
> --- Masquerade, Appletalk, etc.
> The Linux Networking Overview HOWTO:
> http://howto.tucows.com/otherhowto/Networking-Overview-HOWTO
>
> If I were you, I would try things until something breaks,
> rather than ask what to try. It is easier for people to
> speculate about the cause of a problem than it is to
> recommend how to avoid problems.
>
> BUT...if you're still reading, I suggest this (ordered) list
> of things to try:
>
> 1) Gotta make sure networking is up on Linux. Usually the best
> measure of this is to use the "ifconfig" program to look at the
> current interfaces, and if you don't see an "eth0" interface,
> use an

>  # ifconfig eth0 192.168.1.1 netmask 255.255.255.0 broadcast 192.168.1.255
> and see if "ifconfig" shows an "eth0" interface then. If ifconfig
> won't configure or show a physical (not "lo") interface, then
> read the Ethernet HOWTO.
>
> 2) Once ifconfig shows an "eth0" interface with reasonable numbers,
> (See the Networking HOWTO or the NAG for elaboration), try
> pinging eth0's IP number; something like this:
>  # ping 192.168.1.1
> If you can't ping your local eth0, see the HOWTO or NAG.
>
> 3) Once you CAN ping your local eth0, see if there's a telnet
> server listening:
>  # netstat -an
> Look for some lines like this:
>
>   Active Internet connections (servers and established)
>   Proto Recv-Q Send-Q Local Address           Foreign Address         State
>   tcp        0      0 0.0.0.0:23              0.0.0.0:*               LISTEN
>
> That would be a tcp service listening to port 23
> (the well-known Telnet port) on all interfaces.
> It's probably inetd, not telnetd itself, but you
> MUST see a line like this or there's no hope.
>
> 4) Once someone's listening on port 23, try it:
>  # telnet 127.0.0.1
> and see if you can connect to yourself. Some people
> would put this step first, before bothering with eth0
> and stuff, but who cares what some people think?
> If it doesn't work, try "telnet -v", and snoop around
> files in /var/log/ for error messages from inetd or
> telnetd as to why it won't respond.
>
> 5) Once you can connect locally, you want to ping
> the Linux eth0's IP address from another machine.
> Does Mac have a ping? I don't know. Configure the
> Mac TCP/IP to be 192.168.1.2 or some other IP that
> is different, but a close neighbor of the Linux IP,
>  and try to ping the Mac IP from the Linux:
>  # ping 192.168.1.2
>
> 6) When that works (double-check the "ifconfig"
> settings for eth0 in Linux and the TCP/IP control
> panel in the Mac, and then try a different cable),
> go to the Mac and use Nifty Telnet to connect to
> the Linux IP address (192.168.1.1 in this example)
>
> 7) Name resolution is harder, and is covered in the
> HOWTO and the NAG above. Linux and Mac and Windows
> can use text files as a substitute (hosts file),
> but the Mac needs a different format - rather like
> a DNS zone file.  The Mac Help system will lead you
> to the Apple site with instructions for this.
> I definitely recommend hosts files instead of DNS
> at least until you get telnet working!
>
> Try it with the PC - just telnet 192.168.1.1.
>
> 8) If you got steps 1-5 OK and each machine can
> ping the other by number (possibly by name if
> you play with the hosts file at each end), and
> something's listening on TCP port 23, and
> telnet still doesn't work, it could be several
> things. I won't bother to enumerate them. The
> telnet server may be refuse connections if it
> is unable to complete a IP-number-to-hostname
> translation; signs of this would appear at the
> end of log files in /var/log/.
>
> write back to the list with success/failure! bye!
>
> Chris Bopp
>
> ---
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