Configuration Help with Cisco MS250-24P

[RoudyFocx]

Hello everyone,

I am fairly new to networking and have been tasked with configuring a cisco switch. Our set up is simple, we have 4 devices that need to get out to the internet. We have a comcast EDI line with an L2 cienna switch provided by comcast. 

Here are the details provided by comcast: 

	Customer Usable IP Information (WAN Block) >>>>>> LAN Block >>>
Link IP Address:	50.x.x.184/29	Usable IP Block:	50.x.x.192/28
Gateway:	50.x.x.185	Usable IP Ranges:	50.x.x.193-50.x.x.206
Layer 3 IP:	50.x.x.186	Usable Subnet Mask:	255.255.255.240
Layer 3 Subnet Mask:	255.255.255.248	Usable IPv6 Block:	N/A

When I go to enter the  L3 information from the meraki dashboard I run into this error: 

How do I get this to access the internet? 

[GIdenJoe]

Hey,

From the not redacted parts I can make out you made a small error in the Subnet part.  The subnet is 50.x.x.184/29 not 50.x.x.0/29.  Meraki is holding your hand here and rightfully complaning that 50.x.x.185 is not within the same subnet as 50.x.x.0/29 which would only encompass 50.x.x.0 through 50.x.x.7 instead of  what you need: 50.x.x.184 through 50.x.x.191.

So your interface IP of 50.x.x.193 will also not work since that is in the next subnet.

So this setup, is this like a private WAN setup where you only get one routed subnet and that internet NAT is happening upstream?

Best of luck!

[RoudyFocx]

Hello,

Thanks for your response, I have since entered .184/29 and was able to create my interface and static route. Now my issue is that i get the message "Has never connected to the Meraki cloud". 

This is not a private WAN set up, instead comcast gave up a copper hand off and our L3 switch is plugged into their L2 device. I am a novice at networking and thought we would need a router connected to the switch to get out to the internet but our Cisco rep said a L3 switch could do the job. 

Right now the topology is: Comcast Ciena 3924, Port 1, Copper Handoff > MS250, Port 24 > 4 end devices (static IP) 

I guess my main issue is how do I get a computer attached to this switch in order to have internet access - is this plug and play or are there more configs that need to happen? 

[GIdenJoe]

I can't speak to the intricaties of those internet connections in your area.  Usually in the IPv4 world you have public and private addressing.  So a router does the translating between your internal subnets and an external IP address.  Sometimes you have the ISP router itself that does the translation so you only get private IP addresses behind the ISP.  But you will have to talk to them how it is.

However in other cases you get a public IP directly on your router/firewall and it does the NAT.

A switch does not do NAT.  So I believe in your case the ISP is doing the NAT but once again check with your ISP and they private the subnet that lives between their router and your device and also route that second /28 space towards the IP you are supposed to set in your routing table.

One important aspect with Meraki L3 switches is that you have those SVI's you want to install for your user traffic.  However your switch needs a separate management IP to actually talk to the Meraki cloud to receive it's config.

So in your /29 range you should use another IP for your switch itself and also point to the same default gateway.  And then your switch should eventually reach the cloud.  (white led instead of orange)