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tcp/ip problem

Posted on 2002-05-15
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Last Modified: 2010-04-13
I have two computers. They both run Windows 2000.
I connect them with a twisted cable.
I have installed on both of them:
Client for Microsoft Networks
File and Printer Sharing for Microsoft Networks
NetBEUI Protocol
Internet Protocol(TCP/IP)

If I ping from one of them, any of the two, it works.
If I pint from the other one, it only works to ping itself. Pinging the other one does not work.

Can't figure you why.

To clarify even more.
On the computer that can has a problem with tcpip, if I type netstat -a I can see all the servers running.
If I type telnet localhost(or ip adress) port, it tells me that it can not connect.
If I have the same server, running on my other computer, on the same port, and I do the same at a dos
prompt on the other computer, telnet works.
However if I try to telnet from the bad computer to the good one, same port, it tells me it can not
connect.

There is a problem on my "bad" computer with how tcp/ip works. However, on the "bad" computer, I can
still ping the bad computer and the good computer.
From the good computer I can ping only the good computer.

Hope that clarifies it a bit.

Thanks.
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Question by:simi
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by:EricWestbo
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Hey, Simi...

A bit confused on this.  If you could help clarify a bit...

You have 2 computers, #1 and #2.
What happens when you ping FROM #1 TO #2?
What happens when you ping FROM #2 TO #1?

Also, what are the IP addresses and Subnet addresses for each computer?  Default gateways?

Give us some more info on the settings...

/ew
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by:simi
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#1 - alias BAD
#2 - alias Good

I am on BAD.
I ping BAD it works.
I ping Good it works.
I netstat -a it shows all the running tcp/ip servers with ports.
I try to telnet localhost <such_a_port> it does not work

I am on Good.
I ping BAD it does not work.
I ping Good it works.
I netstat -a it works.
I try to telnet localhost <such_a_port> it works.

Hope that is more clear.
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by:simi
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Ip adresses
BAD IP 169.254.0.1
    Subnet mask 255.255.0.0
    Gateway nothing

Good IP 169.254.0.2
     Subnet mask 255.255.0.0
     Gateway nothing

BAD has two Ethernet cards. One is connected to cable internet. The other one is connected to Good. However I disabled the connection to the Internet and nothing has changed.
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by:simi
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Also if I try being on BAD to telnet to Good to a port that runs a server it does not work. The same port that worked when I telneted from Good to Good.
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by:EricWestbo
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Ok, a little clearer now.

Try setting the default gateway for GOOD to 169.254.0.1, this way BAD knows how to reach the other computer.

Try to ping 169.254.0.1 from GOOD at this point.

/ew
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by:simi
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OK. I'll do that.
Unfortunatelly I can't do it right now, even if I would like to. The computer is on my son's room and he is sleeping(24.40 here).
However, a thing that confuses me is that, regardless that there are two computers. BAD, can not telnet to itself, on a port where I have a server running.
This is why, working on BAD I can not connect to a MySQL running on BAD from a java program running on BAD.
So even if I will fix the comunication between Good and BAD, still if BAD has this problem I am in trouble, unless I will install the database server on Good and connect to it from BAD, in case BAD will be able to connect after changing the Gateway on Good to the same ip as BAD(which is what you sugested).
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by:simi
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Sorry a little confused here.
Bad can ping Good.
So even if I fix the problem with the Gateway, I will eventually be able to ping from Good to BAD too.
But BAD is my development computer.
I need to run a MySQL server either on BAD or on Good but to connect to them from BAD.
The problem is that, for some reason, BAD does not want to connect to a server even running on itself.
Perhaps for the same reason, it does not want to connect to a server running on Good eather, even if, I can ping Good from BAD.
So even if ping will work both ways, I have the problem of not being able to connect to the running database server.
The documentation for the server says that one should telnet to that port to see if everything is OK.
I have installed the database server on each machine, to test.
Again, being on BAD and telneting to BAD on port 3306 I get a message telling me that I can't connect.
Being on Good and telneting on Good on port 3306 it does it.
Being on BAD and telneting to Good on port 3306 it does not work.
This is my real problem, pinging is just a first testing tool.
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by:EricWestbo
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I understand that you have several issues you want to resolve, Simi, but you need to take it one step at a time.  If you can't ping one another, none of your other services are going to work.  Fixing the ping problem will NOT resolve all your issues, but it's the first place to start.

That said, how did you make out when changing the gateway?

/ew
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by:ocon827679
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Sounds to me like you have your network cards in Bad mixed up.  Are you sure that the NIC that connects to Good is 169.254.0.2?  It would make sense as Bad can ping itself and Good, but Good can't ping Bad.
Are you running firewall software on Bad?  Maybe that's why telnet won't work.  
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by:EricWestbo
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Good point from Ocon... but if you have the IPs switched on the cards, you wouldn't be able to access the internet from BAD... it's an internal IP.

Simi... where do we stand?

/EW
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by:simi
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I did set the gateway for Good as 169.254.0.1
Still Good can not ping BAD.
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by:simi
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ocon

The two cards on BAD are.

one that connects me to the cable internet
this one is set up to get an IP automatically.

one that connects me to Good
this one is set up with IP 169.254.0.1
                        mask 255.255.0.0
                        gateway nothing

I don't see how could they be mixed up.

I do not really understand you question
"Are you sure that the NIC that connects
to Good is 169.254.0.2?  "

The card that connects me to Good has 169.254.0.1 as IP

The card on Good has 169.254.0.2 as IP
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by:EricWestbo
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Simi... have you activated ICS on BAD?

http://www.microsoft.com/windows2000/en/professional/help/default.asp?url=/WINDOWS2000/en/professional/help/HowTo_share_conn.htm

this might be the root of your problem, because the ip addresses and subnets all make sense... but we didn't explore ICS

Let us know

/EW
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by:simi
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No.
It is not activated.
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by:simi
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Maibe that helps too.
If I want to uninstall TCP/IP on BAD(just tried uninstalling then installing again), I get an error message telling me I can't cause other services are using it. And Simple TCP/IP services are mentioned.

Even if I go on Services, and Stop the Simple TCP/IP service, still can't uninstall TCP/IP.

I checked on Good, and I do not have the Simple TCP/IP service at all.

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by:ocon827679
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All I was getting at was it sounds like it has to be simple.  Think about it, Bad has 2 NICs.  It can ping Good but Good can't ping it.  If the cards (really just the wires) in Bad were reversed, I would still expect Bad to ping Good.  It can broadcast out on either wire.  But Good wouldn't be able to ping Bad in this scenario.  Sounds kind of like your problem.
My question is "are you sure that the NIC in Bad configured with IP 169.254.0.1 is in fact the NIC that is attached to the same segment as Good (configured as 02)?" I think I had .01 and .02 confused above, no biggie, the important thing is that these NICs are on the same segment.  Another question (and I realize that you wrote it above) are you certain that the subnet addresses are the same, 255.255.0.0?  This can cause similar problems.
EricWest has a good point about the Internet NIC, but you've turned off Internet to TS this problem.  Can Bad still got out to the Internet?  If you had the cards (wires) reversed, I would assume no.  
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by:simi
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Maibe that helps too.
If I want to uninstall TCP/IP on BAD(just tried uninstalling then installing again), I get an error message telling me I can't cause other services are using it. And Simple TCP/IP services are mentioned.

Even if I go on Services, and Stop the Simple TCP/IP service, still can't uninstall TCP/IP.

I checked on Good, and I do not have the Simple TCP/IP service at all.

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by:simi
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ocon.
I disabled one by one the two connections and the behavior was OK. When I disable the one that connects to internet, the connectio to the internet does not work and when I disable the other one the connection to Good does not work.
So I do not see that as a problem.
On the other hand ipconfig shows all the ip adresses corectly. The one that connects to the internet is dynamic, so I can not possible have them mix up.
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by:simi
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ocon.
I disabled one by one the two connections and the behavior was OK. When I disable the one that connects to internet, the connectio to the internet does not work and when I disable the other one the connection to Good does not work.
So I do not see that as a problem.
On the other hand ipconfig shows all the ip adresses corectly. The one that connects to the internet is dynamic, so I can not possible have them mix up.
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by:EricWestbo
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Here's my suggestion at this point:

Go into BAD's device manager & delete the two NIC cards... go into the network connections & remove your settings, then reboot.  Allow the system to auto recognize and configure the two NICs, ensuring that your Microsoft Client and TCP/IP are reinstalled.  Configure ICS.

Go into GOOD's device manager & delete the NIC... go into the network connections & remove the settings, then reboot.  Allow the system to auto recognize and configure the NIC, ensuring that your Microsoft Client and TCP/IP are reinstalled.

Check your internal IPs/subnets on both internal NIC cards, ensuring that you are in the same domain/workgroup.

With all this done, you've pretty much reestablished your network entirely & should be set to go.


let us know
/EW
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by:simi
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I am doing it.
However, again, my main problem is that I run a MySQL server on port 3306 on BAD.
Even if I take out the network cards from BAD, I will still not be able to telnet to localhost 3306
I need to be able to telnet to my servers running on the same box.
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by:EricWestbo
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one thing at a time... let's make sure your two systems can see each other & then we'll worry about getting the services up and running.

if the two can't talk to each other (ie: ping each other), then settin gup your SQL server isn't going to be of any help & will just confuse the matter.

:D

/EW
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by:simi
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My priority is to be able to connect on BAD from a java application to MySQL running on BAD.
The whole thing with two computers I explained just in case that it could help in the process of figuring out what the problem is.
I can even ignore the connection between the two computers.
My problem is that I have this BAD computer where I run MySQL but I can't connect to it from a java application or anything else over TCP/IP.
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by:simi
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Did the uninstall of the cards and the same thing.
Nothing has changed.
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by:simi
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This is what comes when I type netstat -a on BAD

Active Connections

  Proto  Local Address          Foreign Address        State
  TCP    simi:ftp               simi:0                 LISTENING
  TCP    simi:smtp              simi:0                 LISTENING
  TCP    simi:http              simi:0                 LISTENING
  TCP    simi:epmap             simi:0                 LISTENING
  TCP    simi:microsoft-ds      simi:0                 LISTENING
  TCP    simi:1025              simi:0                 LISTENING
  TCP    simi:1027              simi:0                 LISTENING
  TCP    simi:1032              simi:0                 LISTENING
  TCP    simi:1036              simi:0                 LISTENING
  TCP    simi:3306              simi:0                 LISTENING
  TCP    simi:5101              simi:0                 LISTENING
  TCP    simi:44442             simi:0                 LISTENING
  TCP    simi:44443             simi:0                 LISTENING
  TCP    simi:1036              cs36.msg.sc5.yahoo.com:telnet  ESTABLISHED

if I type

telnet localhost 3306

I get:

Connecting To localhost...Could not open a connection to host on port 3306 : Con
nect failed

It looks that BAD does not allow a telnet connection to a server running on a port. Why ?





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by:EricWestbo
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Simi, if you can't get these machines to ping each other, then there's no way you can get them to talk to each other via telnet, ftp or anything else.  No ping = no access.

You need to resolve the root problem before you can start tackling other issues.

If your phone connection is dead, you don't pick it up and start yelling through it in hopes that your neighbor can hear you... likewise, let's get the ping resolved first.

:D

Ok, now that you've reinstalled the NICs and reset their settings, what *exactly* happens when you attempt to ping:

1) from BAD to GOOD
2) from GOOD to BAD

Just let me know either "reply", "timeout", or "unknown"
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EricWestbo earned 50 total points
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SIMI... don't bother with the previous... I think we have something.

Q: are your NICs set up to obtain the IP addresses automatically?  If so, you're going to need to look at your DHCP server before they will ever communicate with each other.

I don't know why I didn't see this before... I *knew* something was wrong with the addresses...

When a DHCP client boots up, it looks for a DHCP server to obtain an IP address, subnet mask, and other possible DHCP options configured on the server. If the client is unable to obtain a lease from a DHCP server, the client uses APIPA and automatically configures itself with an IP address from the Microsoft-reserved IP address range of 169.254.0.1 through 169.254.255.254. The Internet Assigned Numbers Authority (IANA) has reserved this range for private IP addressing, so no one can use it on the Internet. The client also configures itself with a default class B subnet mask of 255.255.0.0. A client uses the self-configured IP address until a DHCP server becomes available.  Your network is not providing that DHCP connection.

Once you establish the DHCP server, you'll obtain good IP addresses, will be able to ping each other & anyone else interested & will be able to complete your ultimate goal of communicating via TCP/IP to you SQL server.

Feedback??

/EW
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by:simi
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I fixed it yesterday.

How I fixed it ?
Old Microsoft way. I formated my hard drive and reinstalled the operating system. Fortunatelly, I am set up such that nothing sits on the partition where I have my OS. Previous good experiences wih Microsoft Products.

About your last email.
The problem, again was not only that the two machines could not ping properly. My main problem was not being able to use a MySQL server installed on BAD. Even if I had only BAD, still I had a problem.
BAD was set up to obtain dynamically an IP adress, on the network card connected to my cable, and had a fixed IP adress on the one connected to Good.
So that was not the problem.
On the other hand, I allready said that ipconfig gives me correctly the IP adresses, both the one that was fix for the internal network, and the one that was dynamically obtained from my cable provider.
So, again , that could not be the problem.

What I suspect it was, was something got corrupted in the OS. I could ping from BAD to BAD but I could not telnet from BAD to BAD or anything else. I could ping from BAD to Good but could not ping from Good to BAD.
BAD had some problems responding when pinged by other machines as well as responding to telnet calls, as well connecting through telnet.

Anyway you made an effort to fix my problem so I will assign you the points. Thank you.
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by:EricWestbo
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Glad to hear it's resolved, Simi.  Best of luck to you.

/EW
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