eemoon
asked on
Where is gateway ip address in wirelesss PC?
Please see below topology
WLC --------------- Nexus7k ---------------- Catalyst4500 ------------ AP - - - - - - - PC
In WLC, management valn6, ip address 10.1.6.5, and wlan vlan7 ip address 10.1.7.7.
In Nexus7K, port connected to WLC are allowed to pass vlan6 and vlan7. Port connected to Cataly4500 is layer3
In Catalyst, port connected to Nexus7K is layer3, and port connected to AP is layer 2 with access vlan6.
In AP, static ip address is 10.1.6.6, gateway ip point to 10.1.6.1 which is located at Catalyst4500 where 10.1.6.0 is advertised by eigrp
In PC, command ipconfig shows the gateway is 10.1.7.1
After checking config in all these devices, this gateway ip address 10.1.7.1 does not exist in all these above devices. My question is where the gateway ip address? It is located at another device?
WLC --------------- Nexus7k ---------------- Catalyst4500 ------------ AP - - - - - - - PC
In WLC, management valn6, ip address 10.1.6.5, and wlan vlan7 ip address 10.1.7.7.
In Nexus7K, port connected to WLC are allowed to pass vlan6 and vlan7. Port connected to Cataly4500 is layer3
In Catalyst, port connected to Nexus7K is layer3, and port connected to AP is layer 2 with access vlan6.
In AP, static ip address is 10.1.6.6, gateway ip point to 10.1.6.1 which is located at Catalyst4500 where 10.1.6.0 is advertised by eigrp
In PC, command ipconfig shows the gateway is 10.1.7.1
After checking config in all these devices, this gateway ip address 10.1.7.1 does not exist in all these above devices. My question is where the gateway ip address? It is located at another device?
If the PC is getting its addresses by DHCP, then the gateway IP address is being obtained from the DHCP server for the subnet it is on, as part of the DHCP request.
Dr. Klahn is correct. Run ipconfig /all on that computer. You'll see one block of information related to that 10.1.7.1 gateway. You'll see in that block whether it is using DHCP or not. If it is using DHCP, then you'll see the address of the DHCP server it is using. If it is not, then it's configured manually in the computer.
ASKER
Thank you for your fast reply.
ipconfig shows the PC get ip address from dhcp via wireless. the gateway address 10.1.7.1 might be dhcp server. But we cannot see the address 10.1.7.1 in all the above devices. The question is where is the device that ip 10.1.7.1 exist at?
ipconfig shows the PC get ip address from dhcp via wireless. the gateway address 10.1.7.1 might be dhcp server. But we cannot see the address 10.1.7.1 in all the above devices. The question is where is the device that ip 10.1.7.1 exist at?
The question is where is the device that ip 10.1.7.1 exist at?
The DHCP server is returning the gateway address 10.1.7.1 as part of the information provided to the client. However, that doesn't mean that 10.1.7.1 has to exist. It only means that the DHCP server that the system used is saying "Use this as your gateway." It's entirely possible that there is a (probable) misconfigured or (improbable) rogue DHCP server on the network.
The DHCP server is returning the gateway address 10.1.7.1 as part of the information provided to the client. However, that doesn't mean that 10.1.7.1 has to exist. It only means that the DHCP server that the system used is saying "Use this as your gateway." It's entirely possible that there is a (probable) misconfigured or (improbable) rogue DHCP server on the network.
ASKER
No misconfigured because all users have this. It's possible there is another non cisco device there, but we cannot see it.
No misconfigured because all users have this.
To me at least, when all users have an incorrect address that very strongly points at one or more of the DHCP servers being misconfigured.
To me at least, when all users have an incorrect address that very strongly points at one or more of the DHCP servers being misconfigured.
Ignore the gateway IP for a moment. What address is listed for the DHCP server itself? That will give you a clue if it is a misconfigured known DHCP server or if it is an unknown DHCP server.
A "brute force" way to track down that server is to run: ping -t 10.1.7.1 from one of the workstations, note that it gets replies, then start unplugging cables from the switch. When you see the pinging fail you'll have a clue of the physical route to the DHCP server.
A "brute force" way to track down that server is to run: ping -t 10.1.7.1 from one of the workstations, note that it gets replies, then start unplugging cables from the switch. When you see the pinging fail you'll have a clue of the physical route to the DHCP server.
ASKER
ipconfig shows that ip address 10.1.7.1 is gateway ip address that every PC get via wireless AP. I noticed in this Nexus7K, there is static ip route pointing to 10.1.7.1 and N7K can ping the gateway, but cannot traceroute it. Apparently the ip is located at another device. Actually it is firewall. I wonder how the traffic go from PC to internet.
What address does it show for the DHCP server (not the gateway)?
ASKER
From PC (via wireless) ipconfig, dhcp server is 1.1.1.1, while we can see wlc have an assigned dhcp server address in different subnet 10.1.10.3, but the dhcp server is connected to N7K.
1.1.1.1 is a very odd address for the wireless PC to see as a DHCP server. That's a public address. Could that be a typo for 10.1.1.1? Whatever the case, the key is that the wireless PC is getting its settings (including the 10.1.7.1 gateway address) from that DHCP server. This assumes that the gateway address isn't somehow statically assigned in the wireless PC.
ASKER
Its 1.1.1.1 when typing ipconfig at PC. When looking at WLC5500 interface, i notice the virtual under Interface Name is 1.1.1.1 Do not know what relation these two same ip address.
I'm not familiar with configuring the WLC5500 but that certainly appears to be where your problem is. It is acting as a DHCP server at 1.1.1.1 and is giving out a gateway address of 10.1.7.1. I would expect that it should have a private address and either needs the DHCP server disabled or configured correctly.
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