Lost

[bligher]

Hi, i am sure most of you have see this before, but i am at a loss.  Trying to configure a cisco sg500(layer2) and a sg500x(layer 3). i would like to be able to route traffic back and forth from hosts on the layer 2 (192.168.100.x) with subnet 255.255.255.0  trough to the hosts on the layer 3 172.16.1.x with subnet 255.255.0.0.  Both just using VLAN1. I have set up a trunk port on each side to connect to each other.  If i bind ip's to my nic from both 192 and 172 i can see both sides, but if i use only one from either side, i cannot ping the other side.

Thanks

[Georg Pauwen]

Hello,

not sure what you have configured, but if you use hosts in different address spaces, you need two Vlans, and configure inter-Vlan routing on the SG500x.

Below a lnk to a video where a friendly lady explains how to do that...

https://video.cisco.com/video/5993827197001

[Richard Burts]

If I am understanding the original post correctly there is a single vlan (vlan 1) and 2 IP subnets. I have a couple of comments about that:

- if there is only a single vlan then there is no point in configuring any switch port as a trunk. They should all be access ports.

- if it is a single vlan then there is not really a need for routing. Every device connected to the vlan should be able to communicate directly with every other device in the network by arping for the destination address . The real question is whether all of these devices WOULD arp for the destination address. The IP stack in many devices will arp only for addresses that it considers to be in its own subnet. This is the fundamental reason for the suggestion by @Georg Pauwen that when there are 2 subnets that there should be 2 vlans (and something to provide inter vlan routing).

[bligher]

Thanks, i was able to follow:

https://video.cisco.com/video/5993827197001

and got it to work exactly in the video but i was trying to use different subnet masks and different class ip's 172.16.x.x  with 255.0.0.0  for vlan1 and 192.168.100.x  for vlan2 with 255.255.255.0. I was able to go from the 198 side to the 172 side, but was unable to go from the 172 side back to the 198 side, even though i could ping the gateway 192.168.100.2 (used as the interface setting).

Thanks

[Richard Burts]

I am glad to hear that using that video you were able to make some progress. I am surprised that you are able to get from 198 to 172 but not able to get from 172 to 198. Perhaps you can give us some details of what you have configured to help us find out what is going on?

[bligher]

After getting it to work following the video, I changed the configuration to:

Vlan 1   172.16.1.3   255.255.0.0

Vlan 2   192.168.100.3  255.255.255.0

Laptop 1 172.16.1.5  255.255.0.0  gateway 172.16.1.3

Laptop 2  192.168.100.100  255.255.255.0  192.168.100.3

Port GE2 is in VLAN2  - laptop 2 is in this port

Port GE1 is in VLAN1 - laptop 1 is in this port

All ports are Access Ports

The only thing i noticed was that when i first configured the layer 3 switch following the cisco video. It automatically made  port GE2 an excluded membership type (clarification on why would be helpful) and all the rest remained untagged. So now with my changes, i have no issues pinging from the 192 side to either the switch or laptop on the 172 side.  Going from the 172 side i can ping 192.168.100.3 but not the laptop at 192.168.100.100. The only difference i see from the video and my configuration was that both vlans had the same subnet mask whereas mine are different.