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Beginner

SG350 DHCP being blocked intermittently

Our office recently updated our switch from a 28 port SG300 to a 48 port SG-350-52MP. We immediately started having intermittent problems with DHCP after the swap.

This issue affects all VLANs, wired and wireless. Some devices are completely unable to get an address, some get one after a very long delay (up to an hour) and some devices connect immediately.  We are yet to determine a pattern. Windows, OSX, Android and IOS all have the same issue

We can ping all connected devices from their perspective network. The switch, firewall, and AD server are running game latest firmware.

 

Network Setup:

1 Firewall, 1 Switch, 2 AP’s, and 1 AD server.

The network has 8 VLANs

VLAN 1 is the main Office network /24. The DHCP is being handled by the AD server

VLAN 50 is Guest Wi-Fi. DHCP is being handled by the Firewall

VLANs 2-4,6-8 are Sub-Tenants. DHCP being handled by the Firewall. (I know this is not the best way to setup the network for security reasons. The subtenants were not part of the original design)

 

vlan database

vlan 2-4,6-8,50

 

interface GigabitEthernet46

 description "Conference WAP"

 switchport mode trunk

!

interface GigabitEthernet47

 description "Back Office WAP"

 switchport mode trunk

!

interface GigabitEthernet49

 description Server

 switchport mode trunk

!

interface GigabitEthernet50

 description Firewall

 switchport mode trunk

Covey.png

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3 REPLIES 3
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VIP Mentor

Re: SG350 DHCP being blocked intermittently

I have observered some issue on some version. Deleting DHCP scope and recreating was resolved, try one of the subnet and let us know.

 

what is the firmware version on this device.

BB
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Highlighted
Beginner

Re: SG350 DHCP being blocked intermittently

firmware version that switch was shipped with: 2.4.5.71

Current firmware version: 2.5.0.92

Prior to writing this post I deleted all of the DHCP scopes and the networks from the firewall and recreated them. No Change

The original configuration had the LAN DHCP server running off the firewall with the other VLANs. I moved the DHCP to the AD server earlier this week, there was no change.

As a test I borrowed and older SG300 and connected to our firewall with the two ubiquiti AP's. Everything connected perfectly.

Highlighted
VIP Mentor

Re: SG350 DHCP being blocked intermittently

Good test and undestand you have done all required here, we need to wait for some SMB Tac to address or raise TAC CAse with SMB product.

 

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