Unable to make DHCP relay work

[tschertel]

I'm trying to use the DHCP relay feature, with no success.

I've already tried on a SG300, on a SG350X and now on a CBS350, so clearly I'm letting something pass.
Today I have the CBS350 in my lab. It's connected to the network (port 2, connected to another switch) and I have a cable directly connected from my computer to it (port 47).
I'm doing everything through the web interface, as I'm not a network expert.

That's what I'm doing:
- I create a new VLAN (103);
- I add the port 47 to VLAN 103;
- change port 2 to trunk;
- enable DHCP relay and add the DHCP server (snooping and option 82 are disabled);

The DHCP server has two scopes: the regular one (xxx.xxx.93.0/24) and the new one (xxx.xxx.103.0/24);

Then, when I try to get a new IP, I get a "time out" message:
"An error occurred while renewing interface Ethernet 2 : unable to contact your DHCP server. Request has timed out."

I've tried all tutorials from internet
I've also tried some from Cisco:
https://www.cisco.com/c/en/us/td/docs/switches/lan/csbms/CBS_250_350/CLI/cbs-350-cli-/dhcp-relay-commands.html
https://www.cisco.com/c/en/us/support/docs/smb/switches/cisco-350-series-managed-switches/smb5406-configure-dynamic-host-configuration-protocol-dhcp-snooping.html

Any help would be appreciated.

[MHM Cisco World]

Vlan 1 is up/up 

Vlan 103 is down there is no port with this vlan 

Allow vlan in any trunk or connect it to any static ip pc make it be up and then check dhcp relay in this vlan.

[tschertel]

Sorry, but both VLANs are up.

These are maybe all relevant lines:

ip dhcp relay address 192.168.93.3
ip dhcp relay enable

!
interface vlan 1
 ip address 192.168.93.30 255.255.255.0
 no ip address dhcp
!
interface vlan 103
 ip address 192.168.103.3 255.255.255.0
 ip dhcp relay enable
!
interface GigabitEthernet1/0/47
 switchport access vlan 103
!
exit

[MHM Cisco World]

...

[tschertel]

Could I have forgotten some specific configuration on DHCP server?
How could I troubleshoot this from server's side?

[MHM Cisco World]

Solution 
We troubleshooting many like SVI IP and routing and VLAN UP/DOWN lastly I read some doc. about the CBS350 to find why all your config is OK but still relay is not work Until I found this doc.

https://www.cisco.com/c/en/us/td/docs/switches/lan/csbms/CBS_250_350/CLI/cbs-350-cli-/dhcp-relay-commands.html#wp1753943513

so choose one of two option to config the relay.

[tschertel]

Hi MHM, thanks for your reply.

I do have DHCP relay globally enabled:

switchf27fed#show ip dhcp relay
DHCP relay is Enabled
Option 82 is Disabled
Maximum number of supported VLANs without IP Address is 256
Number of DHCP Relays enabled on VLANs without IP Address is 0
DHCP relay is not configured on any port.
DHCP relay is enabled on Vlans: 103
Active: 103
Inactive:
Servers: 192.168.93.3

And I do have an IP address on this interface:

interface vlan 103
 ip address 192.168.103.1 255.255.255.0
 ip dhcp relay enable
!
...
interface GigabitEthernet1/0/47
switchport access vlan 103
!

[MHM Cisco World]

https://www.youtube.com/watch?v=AIgNYQ6ftjQ

this video to config the DHCP relay in CBS350
let take this way since CLI is confuse me.