[K12OSN] Window Clients can't get past the Linux Server

Steve Jackson sjxn at bigpond.net.au
Fri Oct 5 07:03:34 UTC 2007


That's great! Full marks for persistence.

Where there's a Linux there's a way. :-)

Maybe your solution should be turned into a wiki article.

jones yeates wrote:
> I got it to work.  It was an IPX problem.  I described it on another 
> thread:
> https://www.redhat.com/archives/k12osn/2007-October/msg00051.html
>
> Thanks again for all of your help.
>
>     ------------------------------------------------------------------------
>     Subject: Re: [K12OSN] Window Clients can't get past the Linux Server
>     From: sjxn at bigpond.net.au
>     To: k12osn at redhat.com
>     Date: Tue, 25 Sep 2007 21:58:18 +1000
>
>     Hmmm. I think you need help from someone more familiar than me
>     with the Novell logon process at this point. However....
>
>     As I understand things, the DNS suffix is used when querying DNS
>     servers, and is added to the name of the machine being sought if
>     it is not specified. Thus if your machine name was 'daneel,' your
>     DNS suffix was 'robots.com' and you asked 'daneel' to ping
>     'giskard' without specifying a fully-qualified name such as
>     'giskard.solaria.net' then 'daneel' would query for
>     'giskard.robots.com,' adding its own DNS suffix on to the
>     sought-for name. A connection-specific DNS suffix lets you tell a
>     computer with more than one network interface that it is to use a
>     different DNS suffix on each network it has available. In most
>     cases there is only one network interface and the
>     connection-specific suffix is not needed; but it is set by DHCP
>     anyway, just in case you didn't give Windows a fully-qualified
>     name, or in case that name doesn't work on this particular network.
>
>     I am afraid I have no idea whether this will affect the Novell
>     logon process. To find out, if you place the PC directly on the
>     main network, does it login correctly? What DNS suffix does it get
>     there? What happens if you set that DNS suffix in the DHCP
>     settings on the LTSP server? (The terminals will get this suffix
>     too, but it shouldn't matter AFAIK unless they are running local
>     apps or print servers etc).
>
>     As an aside, I assume you've looked in the log files on the
>     Windows machine, to see if the Novell client is trying to tell you
>     anything. I don't know where Novell would put that information
>     (anyone?), but I would start with the Event Viewer. Also, it would
>     be helpful to see the output of 'iptables -v -L' on the LTSP machine.
>
>     With tcpdump, it's probably only worth doing this if you know a
>     bit about recognising network packets. On the other hand, I see no
>     way to get any further without doing something like it, after
>     proving the logon works with the Windows box on the main network.
>     Others may like to recommend a better protocol analyser for this,
>     such as ethereal - I'm just telling you what I would do, having a
>     limited memory :-)
>
>     I would first try to see what happens on the terminal network,
>     like this:
>     1. Start a command line on the LTSP server and type 'ifconfig'
>     (omit the quotes, they are just for clarity here) to see which
>     network is on which interface - look at the ip addresses for eth0,
>     eth1, etc. Let's say eth0 is the terminal network (with
>     192.168.0.254) and eth1 the main network for what follows. If
>     yours are different, make the appropriate changes below.
>     2. Make sure all other computers and terminals on the terminal
>     network are turned off, to avoid extra traffic or having to use a
>     filter while tcpdump-ing.
>     3. Do 'tcpdump -vv -i eth0 >file0' in the command line on the LTSP
>     server - this causes tcpdump's output to be captured in a text
>     file called 'file0'.
>     4. Turn on the Windows machine (this is so we capture any
>     preliminary lookups it tries before logon).
>     5. Try to log in to Novell when Windows is ready.
>     6. When the login fails, use Ctrl/c on the LTSP server to
>     interrupt the capture.
>     7. Shut down the Windows machine again.
>
>     Now we repeat the process capturing traffic on the main network.
>     You won't be able to shut everything down here, but try to do it
>     at a quiet time.
>     8. With the Windows machine off, do 'tcpdump -vv -i eth1 >file1'
>     on the LTSP server.
>     9. Repeat steps 4,5,6.
>
>     Now compare the two capture files 'file0' and 'file1'. (I suggest
>     doing the two captures separately so that file0 will give you a
>     guide to what is relevant in file1, without having to search hard
>     for it amongst all the other traffic.) The ip addresses (and ports
>     on the LTSP server end) will be different owing to NAT, but you
>     should see an outgoing packet in file1 for every incoming relevant
>     packet in file0 (this is where it gets hard to describe what you
>     are really looking for), and appropriate responses coming back
>     from the DNS and Novell servers on the main network in file1, and
>     being passed back to Windows in file0.
>
>     Look out for repeated requests that give a clue about a response
>     going missing. If you can't work out the order of packets, you
>     could repeat steps 2-6 but using 'tcpdump -vv -i any >file2' which
>     will capture both interfaces at once, in order. Again, look for
>     corresponding packets on each side being relayed by the LTSP server.
>
>     Look out for DNS lookup failures, and also look out for broadcasts
>     other than ARP on the eth0 side (sent to a .255 address) - it may
>     even be that Novell relies on broadcasts to find servers, but I
>     sincerely hope not! It would be instructive to compare the results
>     with a trace of a successful login on the main network, if you can
>     manage that - but Windows has no native equivalent to tcpdump, and
>     I don't know about Netware.
>
>     By the way, I'm using Ubuntu to check the command parameters I'm
>     telling you - they might be slightly different on FC5, but I doubt it.
>     That's all I can think of at the moment. I hope it helps! Good luck!
>
>     On Tue, 2007-09-25 at 05:05 +0000, jones yeates wrote:
>
>         I tried to get the dhcp server to give the client the DNS server ip 
>         addresses on the school's network, and it still didn't work.  As you 
>         mentioned, the Linux thin clients ended up not being able to connect 
>         properly.
>
>         I noticed that the school machines have a different Connection-specific DNS 
>         Suffix  than the LAN and I'm not sure if I should change it to what the 
>         school has or not.  I don't know what that does.
>
>         The Windows clints can ping the DNS servers.
>
>         I installed tcpdump, but I'm not sure how to use it to see the packet flow 
>         from the Window's client.
>
>
>         >From: Steve Jackson <sjxn at bigpond.net.au <mailto:sjxn at bigpond.net.au>>
>         >Reply-To: "Support list for open source software in schools." 
>         ><k12osn at redhat.com <mailto:k12osn at redhat.com>>
>         >To: "Support list for open source software in schools." <k12osn at redhat.com <mailto:k12osn at redhat.com>>
>         >Subject: Re: [K12OSN] Window Clients can't get past the Linux Server
>         >Date: Sun, 23 Sep 2007 08:23:11 +1000
>         >
>         >This sounds like a DNS lookup problem to me. DNS is used to locate domain 
>         >servers in Active Directory, assuming that's what you mean by "tree server" 
>         >- and the same for Novell I think.
>         >To diagnose, I would hand-configure the W2K DNS server entry to be the same 
>         >address as it would get if it were connected to the "main" network, and see 
>         >if it now works. If it does, you need to look at where the LTSP server's 
>         >DNS service is forwarding requests it can't handle to, and make it try the 
>         >"main" network's DNS. If your LTSP server doesn't have a DNS service, 
>         >change its DHCP config to tell the clients to use the main DNS address.
>         >
>         >Transparent proxying only affects web traffic IIRC (and I'm not sure what's 
>         >going on with squid, can't help there). The ip_forward setting must be 1. 
>         >NAT must be used unless the "main" network knows how to route packets back 
>         >into the "terminal & w2k" network.
>         >
>         >Steve
>         >
>         >jones yeates wrote:
>         >>I am using a floppy to boot onto the LTSP server.  It is working fine.  
>         >>The clients can log in and access the Internet. =]
>         >>
>         >>When the client doesn't boot from the floppy, it loads up Windows (2000).  
>         >>It is unable to find the "tree server" to authenticate the Windows user.  
>         >>However, if I say "Yes" to work on the Window's desktop, I can access the 
>         >>Internet.
>         >>
>         >>On the Fedora Core 5 server that is running K12LTSP, I tried:
>         >>     #echo 1 >  /proc/sys/net/ipv4/ip_forward
>         >>and that took care of the Windows client being able to access the 
>         >>Internet.
>         >>
>         >>I tried:
>         >>     #chkconfig --levels 345 transparent-proxying on
>         >>and there was no change so I entered
>         >>     #chkconfig --levels 345 transparent-proxying off
>         >>
>         >>I restarted the server, for another attempt at solving this.
>         >>I turned off the firewall, installed and ran squid.  I made the changes 
>         >>discussed in 
>         >>http://www.redhat.com/archives/k12osn/2007-August/msg00221.html but it 
>         >>failed to #service squid restart.  I removed the transparent value and 
>         >>#service squid restart worked fine.
>         >>
>         >>I tried
>         >>     #chkconfig --levels 345 transparent-proxying on
>         >>again.  This time it couldn't be found.  I listed all the values for 
>         >>chkconfig and it wasn't on the list.  I am not sure how I removed that 
>         >>item, is there a way I can get it back?
>         >>
>         >>Below is what the ipconfig looks like on the Window's client.
>         >>
>         >>E:\>ipconfig /all
>         >>Windows 2000 IP Configuration
>         >>        Host Name . . . . . . . . . . . . : c-23
>         >>        Primary DNS Suffix  . . . . . . . :
>         >>        Node Type . . . . . . . . . . . . : Hybrid
>         >>        IP Routing Enabled. . . . . . . . : No
>         >>        WINS Proxy Enabled. . . . . . . . : No
>         >>        DNS Suffix Search List. . . . . . : ltsp
>         >>Ethernet adapter Local Area Connection 2:
>         >>        Connection-specific DNS Suffix  . : ltsp
>         >>        Description . . . . . . . . . . . : Intel(R) PRO/100 VE Network 
>         >>Connection
>         >>        Physical Address. . . . . . . . . : 00-01-04-EB-12-1C
>         >>        DHCP Enabled. . . . . . . . . . . : Yes
>         >>        Autoconfiguration Enabled . . . . : Yes
>         >>        IP Address. . . . . . . . . . . . : 192.168.0.218
>         >>        Subnet Mask . . . . . . . . . . . : 255.255.255.0
>         >>        Default Gateway . . . . . . . . . : 192.168.0.254
>         >>        DHCP Server . . . . . . . . . . . : 192.168.0.254
>         >>        DNS Servers . . . . . . . . . . . : 192.168.0.254
>         >>        Lease Obtained. . . . . . . . . . : Friday, September 21, 2007 
>         >>4:25:40 PM
>         >>        Lease Expires . . . . . . . . . . : Friday, September 21, 2007 
>         >>10:25:40PM
>         >>
>         >>As a Windows client, I am able to ping outside of the 192.168.0.0 LAN and 
>         >>onto the school's regular network.  I believe nat is working because I can 
>         >>access the Internet on the Window's client.
>         >>
>         >>
>         >>I am not sure what else to try.  The transparent thing is my only guess.
>         >>
>         >>_________________________________________________________________
>         >>Windows Live Hotmail. Even hotter than before. Get a better look now. 
>         >>www.newhotmail.ca?icid=WLHMENCA148
>         >>
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>         >>
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