06-25-2009 11:22 PM - edited 03-06-2019 06:28 AM
hi experts,
i have a 3750G used for a branch office which is connected via MetroE to our main 6509. when i plugged my laptop in one of the ports in the 3750G i can't get an IP address via DHCP. i've already put the 'ip helper-address <dhcp server address>' in the interface vlan. now, i used the 'ip dhcp' service on the switch (which is non-standard and temporary config). i can ping and trace the dhcp server from the 3750G. not sure what i'm missing here. below is the config:
interface Vlan124
description subnet 172.25.124.0/24 access
ip address 172.25.124.253 255.255.255.0
ip helper-address 172.25.22.10
ip helper-address 172.25.22.20
no ip proxy-arp
ip pim sparse-dense-mode
ip dhcp pool Temp_Subnet_124
network 172.25.124.0 255.255.255.0
default-router 172.25.124.253
dns-server 128.x.x.x 128.137.1.3
netbios-name-server 128.x.x.x 128.x.x.x
Solved! Go to Solution.
06-28-2009 12:21 PM
John
In a previous post you said:"when i made a ping from source int vlan 124, i got an error which says interface is not enabled. i did a show ip int bri on this switch and saw that int vlan 124 protocol is down."
I believe that this is your problem. I do not believe that you have an OSPF problem. If you resolve the problem with VLAN124 I believe that your routing will work. (note that IOS will not advertise the subnet of an interface that is not up/up)
Do you have an active device plugged into a port in VLAN124?
HTH
Rick
06-26-2009 12:46 AM
Hello John,
check if there are any forward protocols in global config of the C3750G
sh run | inc forward
eventually you may need to add one for bootp protocol to restore default behaviour.
Hope to help
Giuseppe
06-28-2009 06:55 AM
when i made a ping from source int vlan 124, i got an error which says interface is not enabled. i did a show ip int bri on this switch and saw that int vlan 124 protocol is down. i've checked ospf network statements and can see the other main switch as its neighbors (also checked on main switch, both have ospf configured). i did a no shut but no avail. how can i enable this (can re-creating the int vlan help)?
Vlan124 172.25.124.253 YES NVRAM up down
06-28-2009 07:31 AM
Do you have vl124 in the vl db or otherwise have created the vl on the sw in question?
Jimmy
06-28-2009 09:10 AM
yes. i've created the vlan 124 database and then the int vlan 124.
vlan 124
name 172.25.124.0/24
from this switch, i can see all ospf route towards ds-main switch and sees as its ospf neighbor.
the ds-main switch sees the other route (loopback 172.25.0.124) using show ip route except for the ip address of this vlan 124 interface (172.25.124.253):
ds-main#sh ip ro 172.25.124.253
% Subnet not in table
ds-main#sh ip ro 172.25.0.124
Routing entry for 172.25.0.124/32
Known via "ospf 10", distance 110, metric 2, type intra area
Last update from 172.25.250.41 on GigabitEthernet2/13, 00:29:07 ago
Routing Descriptor Blocks:
* 172.25.250.41, from 172.25.0.124, 00:29:07 ago, via GigabitEthernet2/13
Route metric is 2, traffic share count is 1
i've tried re-creating the vlan database and the int vlan, shut and no shut the interface and also clear ospf process and the routing table but no avail. could this be a bug in the IOS?
06-28-2009 10:38 AM
John,
Please post the configuration regarding OSPF. I'd love to use "sh ip ospf interface brief" to re-check on Sw3750. Do you see Vlan124 there?
Please let me see your "show ip protocol" on Sw3750.
HTH,
Toshi
06-28-2009 12:21 PM
John
In a previous post you said:"when i made a ping from source int vlan 124, i got an error which says interface is not enabled. i did a show ip int bri on this switch and saw that int vlan 124 protocol is down."
I believe that this is your problem. I do not believe that you have an OSPF problem. If you resolve the problem with VLAN124 I believe that your routing will work. (note that IOS will not advertise the subnet of an interface that is not up/up)
Do you have an active device plugged into a port in VLAN124?
HTH
Rick
07-01-2009 04:42 AM
thanks rick! int vlan was up/up when i connected my laptop and vlan was advertised/routing properly in ospf.
07-01-2009 09:07 AM
John
I am glad that you got your problem resolved and that my suggestion was helpful. Thank you for posting to the forum and indicating that the problem is solved and what the solution was. Thank you for using the rating system to indicate that the problem was solved (and thanks for the rating). It makes the forum more useful when people can read about a problem and can know that they will read about the solution to the problem.
HTH
Rick
07-02-2009 12:44 AM
Had a feeling either the vlan wasnt created or nothing was plugged in.
Thanks for the update!
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