dynamic ip can`t access internet while static can

[Emin Aliyev]

Recently i configure 2 ip dhcp pool ,one for Users and one for servers. Everythink worked fine,but  recently users began  complain that they  haven`t internet connection. in Pc i write  ipconfig ,everything is good.but i can`t ping gateway,while static ip pc can ping gateway and get internet connection

For Users i use vlan 87 and for server vlan 85. In switch for user port i change  from user vlan to server vlan,then  get ip by dhcp ,in this condition i have internet .

ip dhcp pool Servers

   network 172.16.85.0 255.255.255.0

   default-router 172.16.85.1

   dns-server 172.16.85.11 8.8.8.8

ip dhcp pool Internet

   network 172.16.87.0 255.255.255.0

   default-router 172.16.87.1

   dns-server 8.8.8.8 4.2.2.2

   lease infinite

[cadet alain]

Hi,

you probably exhausted the Internet pool and so can't get an IP address anymore.

Can you provide output from :

-sh ip dhcp conflict

-sh ip dhcp pool Internet

-sh run | s dhcp

Regards

Alain

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[Emin Aliyev]

No, there is only 20 PC.Pool can`t  be  exhausted

there is no dhcp conflict

sh ip dhcp pool Internet

Utilization mark (high/low)    : 100 / 0

Subnet size (first/next)       : 0 / 0

Total addresses                : 254

Leased addresses               : 2

Pending event                  : none

1 subnet is currently in the pool :

Current index        IP address range                    Leased addresses

172.16.87.5          172.16.87.1      - 172.16.87.254     2

I also try to clear arp and mac table. also same problem

[cadet alain]

Hi,

Can you debug ip dhcp server packet on the server and see if it receives dhcp message and leases out addresses

Regards

Alain

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[Emin Aliyev]

Yes i did it.evrything is ok. can this situation be from poor cablink or bug ?

[cadet alain]

Hi,

so they get an IP from dhcp with correct default gateway  in the correct vlan ?

But they don't get to the internet unless you staically configure them with correct settings ?

That's really strange and if it was a layer2/1 problem then it would be the same with a static IP.

Can you provide quick sketch of topology and all configurations from devices in the path from client to dhcp server(which is also gateway i suppose) but first  is the static config you give to host the same as the dynamic one for it to succeed ?

Regards

Alain

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[Richard Burts]

I notice this line in the original post "but i can`t ping gateway ". I am puzzled how the PC can get an IP assigned and then not be able to ping the gateway (assuming that the gateway is the device that provided the DHCP pool). I think it would help if the original poster would post configs from the device that is assigning DHCP addresses.

Also in re-reading the original post I notice this in the Internet pool

  lease infinite

I would suggest that this be changed. Specify a very long lease if you want. But infinite seems dangerous to me.

HTH

Rick