Switching issue

[vasanthmadugula]

Hi, We have a router with two subnetworks 10.125.x.x/19 and 10.118.x.x/22 configured on the same interface one as primaryip and the other as secondary. And these two subnetworks are connected to LAN through 2950 switch. In the switch there are no vlans configured except native vlan. And i am able to see the ip default-gateway as 10.125.X.X subnet. When i am trying to configure the ip of 10.125.x.x on LAN i am able to reach the router. But when i configured 10.118.x.x on LAN i am not able to. Please let me know any modifications to be needed. Here we dont want to create any VLANs

[glen.grant]

All you should need is to make the 10.118.X.X address as secondary to make it work , that being said any client that has an address in that range must use the 10.118.X.X "router" (your secondary address) as the default gateway setting in their nic card . That is the only thing that would keep it from working if for some reason they had their nic default gateway pointed at the 10.125.X.x address as the default it would not work. Using secondary addresses it has to be routed even though it is on the same interface so the gateway has to be correct.

[Anand Narayana]

Hi Vasanth,

u said u have created primary & sec. ip address on the switch on native vlan 1 interface, is that the layer 3 switch? what is the ip address of the router? if it is a layer 3 switch & if router ip address is a different network which is not in the same subnet 10.118.x.x/22 & u can't ping, then you need to add a static route to it on the layer 3 switch, so that 10.118.x.x/22 clients can ping the router IP.

lemme know how you have configured.

[vasanthmadugula]

Hi Anand,

IP addresses primary and secondary are mentioned on router not on switch. It is L2 Switch. Router ip address is 10.125.96.1 primary and 10.118.224.1 secondary. Now i am able to communicate both the networks. My new question is if any of the network is further subnetted i am not able to communicate. For example i am able to communicate 10.118.224.1/22 network with mas 255.255.252.0. If i am further subnetting with 10.118.224.129/25 with the mask 255.255.255.128 on the PC i am not able to communicate with router ip. i.e; 10.118.224.1. Any thing can be done without using L3 switch to function /25 network.

[Anand Narayana]

Hi Vasanth,

NO, u cannot communicate to 10.118.224.1/255.255.252.0 from 10.118.224.129/255.255.255.128, u will have to use a L3 switch.