Port 10000 problem

Posted on 2004-10-12
Last Modified: 2008-01-09
Hi all.

I'm using the Cisco VPN client.  When I VPN into the network, I need to connect to an application that is running on port 10000 on a host.

I can browse the host's drives, ping it, etc.  I can do everything fine except connect to the application (it's MAS200), which is running on port 10000.  The host and application is up and running as users in the LAN are able to connect.

The firewall is a Cisco PIX 501.  Is there anything special I have to do to disable some kind of port conflict on port 10000 between the PIX and the VPN client?
Question by:surbit
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Author Comment

ID: 12291647
Oh, one more interesting thing.  I can telnet into the host by the IP address on port 10000.  But when I try to telnet into the host via the computer name, it doesn't work.  Yet I can ping the host by the computer name.

So if I telnet 10000, it works.

I can ping host_a and it resolves to

I cannot do this:  telnet host_a 10000.  I do have a WINS server enable for the VPN client.


Author Comment

ID: 12291943
No, the above comment is incorrect.

When I ping host_a, it resolves to, which is the wrong host.  In fact, whatever I ping, it resolves to the same address.  I can even ping a non-existent host such as adfasfasdfasfsafas and it will resolve to  I think this is the problem.  Any solution?  Thanks.
LVL 15

Accepted Solution

Frabble earned 250 total points
ID: 12292235
I guess you're also using DNS to resolve names.
Is there a host entry for host_a in your default DNS domain? Given that non existent hosts resolve, I suspect that there is a wildcard address entry (*) pointing to and presenting you with this problem.
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Author Comment

ID: 12293215
But the LAN users are using the same DNS server and they can resolve all the names properely.

Expert Comment

ID: 12294155
Just permit UDP port 62515 from any host.
This traffic/ports will never be seen with a packet sniffer because this is local to the PC, communication to loopback address (stuff that occur between the VPN softwares different parts)
LVL 10

Expert Comment

ID: 12299505
flush your dns.  

open a command prompt, type ipconfig /flushdns

your VPN client uses port 10000, to make connections to the VPN concentrator.

Expert Comment

ID: 12299549
Actually there are a wide range of ports that are used internally when the VPN client initializes. I had to enable the setting that allows UDP port  62515 to receive traffic from any host to get my VPN working through my XP Firewall. Without that the client will die without even trying to get out of the machine.
LVL 10

Expert Comment

ID: 12299605
yeah, with SP2 for XP, you can add a entries to the windows firewall that will enable the cisco VPN clinets to work.  Here are the only ports that we added.

TCP Port 10000
UDP 4500
UDP 62515

this has worked on many computers.

Author Comment

ID: 12301960
There is no Windows Firewall on the workstation.  Do I need to permit ports on the PIX side?  If so, what are the commands?  Thanks for the inputs thus far.
LVL 10

Assisted Solution

ngravatt earned 250 total points
ID: 12302165
All you need to do is add a rule to the firewall that allows VPN users (whatever thier IP address range is) to have access to MAS200 on port 10000.

There will be no port confict.  The VPN user establishes a connection to the VPN concentrator using a random port as the source.  

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