Connectivity issues within the WAN

Posted on 2009-02-16
Last Modified: 2012-05-06
Trouble with access to random devices from outside or inside the network.  This appears to be a layer 3 issue.  I have access from one device to another on the same subnet depending on the device.  When I reboot the switches and routers, the devices/PC's that I have connectivity between, changes.

This average Windows2003 domain network has VOIP and Data traffic. The Data side has 3 Subnets, 192.168.4.x, 192.168.5.x, 192.168.6.x,
3 Cisco switches at this location and  2 internal cisco routers (for the VOIP). Although I didn't set it up, it's my understanding that the VOIP is on separate subnets. I'm trying to get more information from the VOIP guy so forgive me for not providing more details regarding this.

It's probable that this is a design problem and has existed since the network with VOIP was put in place (1 year ago). I recall that connectivity has failed inexplicably for various devices on occasion since the beginning.

I can reach to the outside from inside on any computer (internet is fine).  
I can RDP from outside to certain devices via VPN connection but only some devices.
RDP from one device on same subnet to another on same (Some work, some don't).
Ping tests confirm success or fail of connectivity (where RDP fails, ping fails)

Question by:egalois
    LVL 6

    Assisted Solution

    Hello egalois,
      Is there anyway you can see how the cisco router is configured?  Cisco creates vlans to separate the voice and the data.  Usually the voice will be on the 10.x.x. network and data goes on the 192.x.x.x network  Also you may find an access-list preventing you from getting to the hosts you are having a problem with.  Last do you have another DHCP server in the network?  The Cisco will be configured as a DHCP so it can hand out addresses to the phone and other devices.


    Author Comment

    Hi danf0x,

    I'm trying to get the login info for the cisco router. The traffic for the phones and data are on separate subnets not sure about the vlans.

    An access-list would be a possibility if the connectivity issues were always between the same devices. But connectivity changes even though the access-lists haven't changed in 1 year.

    The device that I can't connect to has an appropriate address so I think I'm correct in ruling out dhcp (no duplicates either.)   DNS on the other hand....
    LVL 6

    Assisted Solution

    It looks like you may be stuck for a bit without access to those devices.  You can't even look at the arp cache to see what it thinks is out there until you get into the cisco.  
      They didn't even leave you with SDM (Security Device Manger) to configure things as a just in case option?

    Accepted Solution

    Yes, sorry,

    I expect to hear from my associate before the day is through but... The organization I'm with is loosely managed and short on resources. The technician who put the VOIP in should have provided more documentation.  I'm going to force the issue but probably won't see a result for weeks. In the meanwhile, I seem to have temporary access to the device that is needed and I'm too short on time to continue working on this until I get the documentation.  Thanks danf0x for your help!

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