I have 2 Lans and two switches and routers i have the 2 machines with primary and backup Lans primary are connected to primary switch and backup is cnnected to secondary switch . those machines IP adresses are 170.25.1.1--> primary Lan 170.25.2.1 --->secondary LAN 170.25.1.2--> primary Lan 170.25.2.2--->secondary LAN subnet mask is 255.255.255.0 for two lans is same. Default gateway 170.25.11.140 for primary lan machine Default gateway 170.25.12.140 for secondary lan machine if i disable the primary lan of (170.25.1.1) this machine manually by right clicking the network icon and disable it. after this it is pinging to 170.25.1.2 and 170.25.2.2 these machines but if ipull the LAN physically after this if i ping the second machine with is iP 170.25.2.2 it is working fine but if i ping 170.25.1.2 this address it is giving hardware error. Eventhough i pull the LAN it has to ping my secondary machine primary lan 170.25.1.2 for this where to change ? and how to configure my routers to ping other machines if i remove the LAN Please give me the solution am in urgency. appreciate any suggesstions. Thanks KK

It looks as if the issue you faced is: After you disabled the primary network adapter (170.25.1.1) on the machine (we call it computerA), it unable to ping the IP address 170.25.1.2 which is assigned to the other machine (we call it computerB). Additionally, I see that the IP address of default gateway for the secondary network adapter on computerA is 170.25.12.140 but not the IP address where is the same subnet as secondary network adapter (170.25.2.0). It may cause computerA fail to communicate with secondary LAN if its primary network adapter is disabled. To confirm it, would you share me the Route Table on computerA? You may display it by using the command route print.

Hi am posting my actual IPS. After pulling the LAN A am pinging LAN A related other machines .but at this moment it is giving hardware error. but if i ping LANB (which is plugged) related machines it is pinging. To ping the LANA related machines eventhough after removing the LANA what i have to do? THIS IS A MACHINE ROUTE PRINT OUTPUT *===============================================================Welcome to Microsoft Telnet Server.*==========================================================================================================================================Interface List0x1 ........................... MS TCP Loopback interface 0x2 ...00 0b cd 6b 47 ca ...... Compaq NC7781 Gigabit Server Adapter - Packet Scheduler Miniport 0x10004...00 02 a5 46 09 a9 ...... Compaq NC3123 Fast Ethernet NIC - Packet SchedulerMiniport ======================================================================================================================================================Active Routes:Network Destination Netmask Gateway Interface Metric 0.0.0.0 0.0.0.0 174.25.41.140 174.25.41.61 20 0.0.0.0 0.0.0.0 174.25.42.140 174.25.42.61 20 127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1 1 174.25.41.0 255.255.255.0 174.25.41.61 174.25.41.61 20 174.25.41.61 255.255.255.255 127.0.0.1 127.0.0.1 20 174.25.42.0 255.255.255.0 174.25.42.61 174.25.42.61 20 174.25.42.61 255.255.255.255 127.0.0.1 127.0.0.1 20 174.25.255.255 255.255.255.255 174.25.41.61 174.25.41.61 20 174.25.255.255 255.255.255.255 174.25.42.61 174.25.42.61 20 224.0.0.0 240.0.0.0 174.25.41.61 174.25.41.61 20 224.0.0.0 240.0.0.0 174.25.42.61 174.25.42.61 20 255.255.255.255 255.255.255.255 174.25.41.61 174.25.41.61 1 255.255.255.255 255.255.255.255 174.25.42.61 174.25.42.61 1Default Gateway: 174.25.42.140===========================================================================Persistent Routes: None =============================B Machine ===================== *===============================================================Welcome to Microsoft Telnet Server.*==========================================================================================================================================Interface List0x1 ........................... MS TCP Loopback interface 0x2 ...00 0b cd 23 d3c ...... Compaq NC7781 Gigabit Server Adapter - Packet Scheduler Miniport 0x1000...00 02 a5 45 d6 61 ...... Compaq NC3123 Fast Ethernet NIC - Packet SchedulerMiniport =====================================================================================================================================================Active Routes:Network Destination Netmask Gateway Interface Metric 0.0.0.0 0.0.0.0 174.25.41.140 174.25.41.62 20 0.0.0.0 0.0.0.0 174.25.42.140 174.25.42.62 20 127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1 1 174.25.41.0 255.255.255.0 174.25.41.62 174.25.41.62 20 174.25.41.62 255.255.255.255 127.0.0.1 127.0.0.1 20 174.25.42.0 255.255.255.0 174.25.42.62 174.25.42.62 20 174.25.42.62 255.255.255.255 127.0.0.1 127.0.0.1 20 174.25.255.255 255.255.255.255 174.25.41.62 174.25.41.62 20 174.25.255.255 255.255.255.255 174.25.42.62 174.25.42.62 20 224.0.0.0 240.0.0.0 174.25.41.62 174.25.41.62 20 224.0.0.0 240.0.0.0 174.25.42.62 174.25.42.62 20 255.255.255.255 255.255.255.255 174.25.41.62 174.25.41.62 1 255.255.255.255 255.255.255.255 174.25.42.62 174.25.42.62 1Default Gateway: 174.25.42.140===========================================================================Persistent Routes: None am waiting for your reply hope u understood my problem clearly?

Please help me am in urgency.

I found this article in google because I got stunk in the same problem.A probably reson maybe that you switch on the sleep mode of your network adapter,try to switch off it in "My computer-Properties-hardware manager-your network adapter".

Check your cable, you might a cable that both ends are connected to the same switch.

There are a lot of numbers in your first post and your route print that just dont match up. The DG should be the address of a layer 3 device to route traffic to a different network but based on the ip information supplied we are talking about a host IP that exists on a different network than the layer 3 device. what are you using to translate between network segments? from the route print I would ask for an ipconfig /allof the machines if you can. Dislaimer 1:As usual I could be way off so no playing like I'm Frankenstein. Disclaimer 2: my Speeling and proofing skills are teh fail