DHCP discover

[eXPlosion]

I have a router 2811, and PC connected to fa0/1. It cannot receive ip address from router. It should receive from pool 50 (vlan50).

Patg#sh run

Building configuration...



Current configuration : 1693 bytes

!

version 12.4

no service timestamps log datetime msec

no service timestamps debug datetime msec

no service password-encryption

!

hostname Patg

!

!

!

enable secret 5 $1$mERr$/jJFQNiaJSPg5O/2VYM/n777

enable password asdfghj

!

!

!

ip dhcp pool 10

network 192.168.50.0 255.255.255.192

ip dhcp pool 20

network 192.168.50.64 255.255.255.192

ip dhcp pool 30

network 192.168.50.128 255.255.255.192

ip dhcp pool 40

network 192.168.50.192 255.255.255.192

ip dhcp pool 50

network 192.150.50.0 255.255.255.192

!

!

!

no ip cef

no ipv6 cef

!

!

!

!

!

!

!

!

!

!

ip name-server 192.168.50.100

!

!

spanning-tree mode pvst

!

!

!

!

!

!

interface FastEthernet0/0

no ip address

duplex auto

speed auto

!

interface FastEthernet0/0.1

encapsulation dot1Q 10 native

ip address 192.168.50.1 255.255.255.192

!

interface FastEthernet0/0.2

encapsulation dot1Q 20

ip address 192.168.50.65 255.255.255.192

!

interface FastEthernet0/0.3

encapsulation dot1Q 30

ip address 192.168.50.129 255.255.255.192

!

interface FastEthernet0/0.4

encapsulation dot1Q 40

ip address 192.168.50.193 255.255.255.192

!

interface FastEthernet0/1

no ip address

duplex auto

speed auto

!

interface FastEthernet0/1.1

encapsulation dot1Q 50

ip address 192.150.50.99 255.255.255.192

!

interface Serial1/0

no ip address

clock rate 2000000

shutdown

!

interface Serial1/1

no ip address

clock rate 2000000

shutdown

!

interface Serial1/2

no ip address

clock rate 2000000

shutdown

!

interface Serial1/3

no ip address

clock rate 2000000

shutdown

!

interface Vlan1

no ip address

shutdown

!

ip classless

!

ip flow-export version 9

!

!

!

!

!

!

!

!

line con 0

!

line aux 0

!

line vty 0 4

password asdfghj

login

!

!

!

end

[Seb Rupik]

Hi there,

you have created a sub-interface on fa0/1 and tagging the frames with the VLAN 50 ID. it is very likely that the PC connected to this interface will not be configured for tagged frames and will drop them.

The solution is to configure the interface without the VLAN tags:

!
no interface FastEthernet0/1.1
!
interface FastEthernet0/1
  ip address 192.150.50.99 255.255.255.192
!

However the more scalable solution would be to connect a Layer2 switch to Fa0/1 and configure a trunk port connected back to Fa0/1. Then create an access port on the switch for VLAN 50 and connect the PC to it.

cheers,

Seb.

[eXPlosion]

Actually this was done on port fa0/0. Fa0/0 has connected Cisco switch. But the dhcp OFFER only passes to trunk and not vlan10 on switch, where the PC is connected.

I mean there is another PC connected to switch, which has trunk to router f0/0 port.

[balaji.bandi]

you need to configure on router respected port as Trunk port

router example :

interface fa 0/0

switchport trunk encapsulation dot1q

switchport trunk allowed vlan all  (if you want only 50 you can add only 50)

On the Switch side : ( VLAN 50 create)

interface fas 0/0 -- change here respected interface.

switchport trunk encapsulation dot1q

switchport trunk allowed vlan all  (if you want only 50 you can add only 50)

Pc connected port

interface fas 0/2 -- change the real port

switchport mode access

switchport access vlan 50

no shutdown all ports and check all ports up and running.

test and advise.

[eXPlosion]

Router interface has no ability to be switchport interface. It should have subinterfaces an be a router on a stick.

[jcockburn]

Hi Mate,

Seems like the Interface is not in the same IP subnet as the pool...

Take a look at that

Ciao

JC

[eXPlosion]

I changed and router cfg looks

router:

ip dhcp pool 50

network 192.150.50.0 255.255.255.192

Computer is on interface:

interface FastEthernet0/1.1

encapsulation dot1Q 50

ip address 192.150.50.32 255.255.255.192

But still not getting ip

[paul driver]

Hello

From this original configuration, the switchport connecting to this rtr fa0/0 interface need to be a trunk and have it native vlan set to 10.

RTR

no interface FastEthernet0/1.1
default interface FastEthernet0/1

interface FastEthernet0/0.5
encapsulation dot1Q 50
ip address 192.150.50.99 255.255.255.192

ip dhcp pool 10
default-router 192.168.50.1
lease 0 8

ip dhcp pool 20
default-router 192.168.50.65
lease 0 8

ip dhcp pool 30
default-router 192.168.50.129
lease 0 8

ip dhcp pool 40
default-router 192.168.50.193
lease 0 8

ip dhcp pool 50
default-router 192.150.50.99
lease 0 8

Switch
no ip routing
int x/x
description facing rtr
switchport mode trunk
switchport trunk native vlan 10
exit
vlan10-50
exit

int x/x
description pc
switchport host
switchport access vlan 50