06-11-2024 02:52 AM
Hi all,
I have recently migrated two switch extreme network 5420F-24S-4XE in Stack for our customer,
I have encountered an issue concerning DHCP functionality,
Specifically,Although DHCP Relay has been enabled on the switches ,DHCP client are unable to obtain an IP address.
It is pertinent to mention that our client had been utilizing a Cisco switches for several years prior to this transition and without having any problem with DHCP
please note that I have verified that the configuration is configured correctly, from the switch and from the DHCP server side,
I tried to capture the traffic using wire shark , the traffic stop in the switch ,
we request your assistance for this problem, given the critical nature of the DHCP service in the network
thank you for return
Solved! Go to Solution.
06-11-2024 06:53 AM
As Stefan mentioned:
Most Cisco folks forget to enable DHCP-Relay and IP-Forwarding on the VLAN in the direction of the DHCP server (rtlookup <DHCP Server IP>).
Be sure that you've enabled both bootprelay and IP Forwarding on the server VLAN.
https://extreme-networks.my.site.com/ExtrArticleDetail?an=000083193
06-12-2024 02:59 AM
thank you for reply ,
IP forwarding is enabled
dhcp relay is enabled too on both vlans (client + server)
06-12-2024 03:36 AM
Can you share the output of:
show configuration nettools
show bootprelay
show bootprelay configuration
Can you ping the DHCP-Server from the switch?
06-12-2024 05:45 AM
# Module netTools configuration.:
enable bootprelay ipv4 vlan server
enable bootprelay ipv4 vlan user
configure bootprelay vlan user add 10.X.X.252(server IP)
show bootprelay configuration
DHCPv4 BOOTP Relay : Disabled on virtual router "VR-Default", but enabled on sos
Include Secondary : Disabled
BOOTP Relay Servers :
DHCP Relay Agent Information Option: Disabled
DHCP Relay Agent Information Check : Disabled
DHCP Relay Agent Information Policy: Replace
DHCP Relay Agent Source VLAN : None
VLAN DHCPv4 BOOTP Relay
------------------------ ------------------
VLAN "Default":
BOOTP Relay : Disabled
VLAN "user":
BOOTP Relay : Enabled
BOOTP Relay Servers : 10.10.0.252
DHCP Relay Agent Information Option: Disabled
DHCP Relay Agent Information Check : Disabled
DHCP Relay Agent Information Policy: Replace
VLAN "server":
BOOTP Relay : Enabled
please note : if I configure a PC with a static IP , I can ping the rest of the network and the DHCP server
06-12-2024 06:32 AM
This looks good I think. I'm still curious about the "show bootprelay" command as this shows statistics, e.g.:
DHCP/BOOTP relay statistics for virtual router "VR-Default"
Received from client = 63559 Received from server = 61023
Requests relayed = 190677 Responses relayed = 61023
DHCP Discover = 10855 DHCP Offer = 8857
DHCP Request = 51498 DHCP Ack = 49729
DHCP Decline = 11 DHCP NAck = 2437
DHCP Release = 3
DHCP Inform = 1192