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Beginner

Unable to obtain IP from DHCP when Dumb switch connected to Smart switch

I have configure this 2960 and cannot obtain an IP address from a dhcp server connected to random port on the dumb switch. I have port 0/24 as link between 2960 and Linksys SR2016 dumb switch. I have a laptop connected to port 0/13 set as below. The dhcp server is conncted on a random port on the dumb switch. Does the concept of a "native Vlan" on the dumb switch come into play or does that matter? (Would the dumb switch have a native vlan of 1?) I want dhcp requests coming from devices connected to the smart switch to obtain IP addresses across vlan 20 to the dcp server connected on the dumb.

 

2960-24-SFSCS#sh run int fa0/24
Building configuration...

Current configuration : 85 bytes
!
interface FastEthernet0/24
switchport access vlan 20
switchport mode access
end

2960-24-SFSCS#sh run int fa0/13
Building configuration...

Current configuration : 85 bytes
!
interface FastEthernet0/13
switchport access vlan 20
switchport mode access
end

2960-24-SFSCS#

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Beginner

@paul driver "when you say dumb switch do you mean an unmanageable switch correct?" Yes!  Sorry for the terminology. Also, I assumed dumb and see that it actually is manageable. Thanks for correcting me. The issue ended up being ip dhcp-snooping needed to be enabled. I was able to ping throughout the entire network with static IP's and even reach the GW thru the Linksys but when I could not obtain an IP from the dhcp server connected to the Linksys, my assumption was the switch. It is Resolved Now!

View solution in original post

4 REPLIES 4
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VIP Expert

Hello,

 

the Linksys SR2016 has I think a GUI. You need to configure the port on the Linksys as an access port in Vlan 20 as well, because the default Vlan 1 is technically a different network.

 

I have googled for an admin guide and found the one linked below. Go to Chapter 5 --> Vlan Management

 

https://usermanual.wiki/Linksys/LinksysBusinessSeriesSrw2016UsersManual657713.1988589746/html#pf21

Highlighted
VIP Mentor

Hello

when you say dumb switch do you mean an unmanageable switch correct?

if you set an access port on the cisco switch to a specific vlan then the “dumb” switch its ports will all become part of that access vlan.

Also note if the switch ports connecting those switches are not mdix compatible then you require a crossover cable between both switches 



kind regards
Paul

Please rate and mark posts accordingly if you have found any of the information provided useful.
It will hopefully assist others with similar issues in the future
Highlighted

As I read the original post I was thinking like @paul driver that the reference to dumb switch implied that it was an unmanaged switch, on which all ports would be access ports in the same default vlan. But @Georg Pauwen went a step further and found that the SR2016 is a managed switch and is capable of configuring multiple vlans. To be able to provide good answers to the original post we need more information about both of these switches.

HTH

Rick
Highlighted
Beginner

@paul driver "when you say dumb switch do you mean an unmanageable switch correct?" Yes!  Sorry for the terminology. Also, I assumed dumb and see that it actually is manageable. Thanks for correcting me. The issue ended up being ip dhcp-snooping needed to be enabled. I was able to ping throughout the entire network with static IP's and even reach the GW thru the Linksys but when I could not obtain an IP from the dhcp server connected to the Linksys, my assumption was the switch. It is Resolved Now!

View solution in original post

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