PeraHoman
asked on
DHCP/DNS Issue
I have a site that has about 3 workstations, and IPs were statically assigned (configured on workstation and on infoblox (DHCP and DNS records created). There are two switches, a core and access switch, both are LAN base images and use the router (2821) to route. There is only one VLAN (VLAN1). I recently added ip-helper addresses on the router's interface for dhcp/dns (both services are working fine), but when I change the workstation from static to DHCP, it doesn't pick up an IP address.
Ideas:
It''s statically assigned in infoblox and dns records are still there for this workstation. Could this be causing the issue of the workstation not receiving a leased IP?
Should the ip helper be assigned on VLAN 1 on the switches? (A similar site has it on the router's interface)
I will try to get a resource on site to connect to the switch with another laptop.
Router
interface GigabitEthernet0/0
ip address 10.124.117.1 255.255.255.128
ip helper-address 57.2.2.19
ip helper-address 57.2.2.5
no ip redirects
no ip proxy-arp
ip flow ingress
ip route-cache flow
duplex full
speed 100
service-policy input REMARK-TO-ZERO
Core
interface Vlan1
ip address 10.124.117.3 255.255.255.128
no ip route-cache
ip default-gateway 10.124.117.1
interface GigabitEthernet0/1
description Router Gi0/1
switchport trunk allowed vlan 1
switchport mode trunk
media-type sfp
Ideas:
It''s statically assigned in infoblox and dns records are still there for this workstation. Could this be causing the issue of the workstation not receiving a leased IP?
Should the ip helper be assigned on VLAN 1 on the switches? (A similar site has it on the router's interface)
I will try to get a resource on site to connect to the switch with another laptop.
Router
interface GigabitEthernet0/0
ip address 10.124.117.1 255.255.255.128
ip helper-address 57.2.2.19
ip helper-address 57.2.2.5
no ip redirects
no ip proxy-arp
ip flow ingress
ip route-cache flow
duplex full
speed 100
service-policy input REMARK-TO-ZERO
Core
interface Vlan1
ip address 10.124.117.3 255.255.255.128
no ip route-cache
ip default-gateway 10.124.117.1
interface GigabitEthernet0/1
description Router Gi0/1
switchport trunk allowed vlan 1
switchport mode trunk
media-type sfp
lruiz52
If you only have one vlan, you don't need the ip helper command. Check your windows or av firewall, it may be blocking DHCP.
What is the IP address of the DHCP server?
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DHCP servers are not in VLAN 1 subnet, and those are the correct addresses, and they are routable (mpls network). DHCP/DNS addresses are the 57.x.x.x IPs.
Can you ping both of those addresses from a computer in VLAN1 when it has a static IP address?
If you can, then I would double check how DHCP is configured on the DHCP servers. I know you said the DHCP is working, but obviously it is not for requests from VLAN1. If it was working for VLAN1 then you would not be here asking questions about it.
If you can, then I would double check how DHCP is configured on the DHCP servers. I know you said the DHCP is working, but obviously it is not for requests from VLAN1. If it was working for VLAN1 then you would not be here asking questions about it.
Thanks for accepting my answer, but could you document what specifically the problem was? That will help others that have the same problem.