Solved

TCPIP / DNS problem

Posted on 1998-09-04
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Last Modified: 2013-12-23

Hello,

I have TCPIP / DNS difficulties in our LAN
with a terminal emulation software called
"Reflection".



Configuration
~~~~~~~~~~~~~

- Reflection 4.0

- Win95b with MS TCPIP
  (IP Network:            192.1.1.0
   MASK:            255.255.255.0
   IP Adress:            192.1.1.94
   Standard Gateway:      192.1.1.246
   DNS Server:            192.1.1.247)

- Host:             erni
  IP Adress:             192.1.1.1

- ISDN Internetrouter:      192.1.1.246

- DNS server with local hostname records (for example: erni)
  and configured to look up the providers DNS server on
  192.168.2.1 if DNS lookups cannot be served from the local
  database.



If I open a new connection in the reflection term-emu software
of the type "Telnet-mgr" with Hostname "erni" all is fine.
I get the connection immediately. The DNS server is working.
The ISDN - line on router 192.1.1.246 remain closed.


If I open a new connection type "Telnet-mgr" with IP Adress
192.1.1.1 the router on 192.1.1.246 opens the ISDN connection
and after a while erni is responding.


Why opens the router the connection to the internet if I choose
the host by IP Adress? Same happens by reflection - ftp connection.

!!The problem is not there if I use the Win95- telnet.exe or ftp.exe!!

It seems that the reflection software first is asking a host on
the internet before searching the host on the local ip network.
I know that our LAN IP Adress (192.1.1.0) IS A PUBLIC IP ADRESS
(someone made a fault)! Could this be the problem?
Since losts of PCs use the ip adress instead of the host name
this means lots of work changing the reflection profile.


Holger Hussy




Holger Hussy
Herzzentrum Lahr
holger.hussy@gmx.net


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Question by:holger
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Expert Comment

by:ahoffmann
Comment Utility
> the providers DNS server on 192.168.2.1

this seems to be nonsense, 'cause 192.168.x.x is a reserferd RFC
address for private use only. So your provider isn't allowed to
route any TCP/IP packets with such a IP address as source or
destination
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Expert Comment

by:bknowles
Comment Utility
Check ARIN -- 192.168.* is reserved, but it's reserved in the name of a particular college (I think).  Therefore, it is technically routable, it's not not routable for policy reasons.

The RARP answer sounds plausible, and therefore you should have reverse DNS set up on your local nameserver.
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Author Comment

by:holger
Comment Utility
Hello,

following comments:

to ahoffmann:
Please apologize I was wrong with the IP address.
If choosing the host by ip adress, the problem occours only when configuring an DNS Server on the Win95 workstation. If there is no DNS entry in the win95 workstation, there is no problem.

The router shows the following packets during opening the connection:

192.1.1.247 -> 194.25.2.129 Protocol UDP Port 53->53
(this means: my DNS Server [192.1.1.247] opens the router to the DNS Server at our provider [194.25.2.129] for a DNS lookup)

192.1.1.247 -> 192.5.5.241 Protocol UDP Port 53->53 (this means: my DNS Server makes a lookup to another server on 192.5.5.241) The server 192.5.5.241 in in the domain "xfw2-paix.pa.vix.com".

So reflection produces a DNS lookup to the server 192.5.5.241, and NOT 192.168.2.1!!
My DNS server is configured to look up the dns server at our provider in case not able to resolve the lookup of the
client.
This is why the connect goes up.
Why happens that when choosing the host by ipaddress?



To bertc:
Following shows that the local DNS server is working correctly:

C:\>nslookup 192.1.1.1
Server:  www.heart-lahr.com
Address:  192.1.1.247

Name:    ernie.heart-lahr.com
Address:  192.1.1.1


C:\>nslookup erni
Server:  www.heart-lahr.com
Address:  192.1.1.247

Name:    erni.heart-lahr.com
Address:  192.1.1.1
C:\>


Reverse lookups are working correctly.


Holger Hussy


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Author Comment

by:holger
Comment Utility

Further comments:

I have tried it a second time (opening reflection connection to 192.1.1.1 by IP address).
The router shows the following packets during opening the connection:

192.1.1.247 -> 194.25.2.129 UDP Port 53->53
192.1.1.247 -> 202.12.27.33 UDP Port 53->53


The second lookup goes to machine:

C:\>nslookup 202.12.27.33
Server:  www.heart-lahr.com
Address:  192.1.1.247

DNS request timed out.
    timeout was 2 seconds.
Name:    M.ROOT-SERVERS.NET
Address:  202.12.27.33
C:\>


As mentioned above, the first DNS lookup goes to the DNS server of our provider. This is configured in the DNS server. But why the second lookup?

I'm using Microsoft DNS server with NT4.0 SP3.


Holger


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Accepted Solution

by:
bknowles earned 100 total points
Comment Utility
Oh.  Microsoft DNS.  No wonder.  It's broken.  Severely broken.


I suggest you get the Windows NT port of BIND (either the freely available port, or the commercial value-added version), which is the Internet de facto standard program for serving the DNS (e.g., it's used by all the root nameservers, etc...).

Once you've got a properly working nameserver, it'll be a lot easier to debug and fix whatever problems you may have that remain.
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Author Comment

by:holger
Comment Utility
I have worked with BIND but I think it is not very integrated in the NT environment.
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Expert Comment

by:bknowles
Comment Utility
Granted, BIND doesn't do WINS resolution, but at least it is a functional nameserver.  Unfortunately, the bletchery and dreckage from Microsoft isn't, although most people will probably never know the difference.

You might be able to run both of them -- BIND to handle the DNS, and Microsoft's nameserver to handle WINS and simply pass DNS queries on to BIND.  However, I don't know exactly how that would be done.


Thanks and good luck!
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