APIPA Issues in LAN

[gauravpundir231]

Hi All,

We are facing lot of apipa issues in our LAN network. Below are the details:

1.DHCP server is working fine. Other desktops/laptops are picking up valid IPs in the same VLAN.

2. DHCP is in different subnet.

3.Have checked configuration from switch side. Desktop is in required VLAN. Cleared the counters. Tested with another LAN cable.

4. VALN scope is not full. Many usable IPs are there.

5. Did release/renew. No change.

6. This is happening for random systems at random times

Please help and advise what other things can be done to resolve this issue.

[Spooster IT Services]

Hi Gaurav,

Can you please send me the configuration of the switch along with network topology?

It can be due to wrong configuration on the switch if this is manageable switch, due to bad switch, due to bad cable, due to bad LAN card. 

[gauravpundir231]

Hi

Cant send configurations due to company's policy.

is the SVI or Layer 3 interface configured with ip helper-address?: SVI

Is the switch configured with DHCP Snooping? No

I have checked with different LAN cables as well

Desktop-->Access SW-->Core SW

[Julio E. Moisa]

Ok thank you,

Are the servers network configured at the same location and same Core switch?

(Different device or location) for these SVI do you have something like:

interface vlan 10
description LAN1
ip address 192.168.10.1 255.255.255.0
ip helper-address 172.19.20.25  
ip helper-address 172.19.20.26 

Where the IP addresses 172.19.20.25 & 26 are the DHCP servers. Other question, what access switch model are you using?

[gauravpundir231]

HI Julio,

Access and core switches are in different floor same location. DHCP is in different location

SW Model:3750 & 3850

[Julio E. Moisa]

Hi 

Thank you for the information, if the DHCP is a different location you need to use ip helper-address command.

Now you could configure a static route, and verify:

Ping to the gateway of this VLAN
Ping and traceroute to the DHCP server. 

It will useful to discard communication problem. 

[gauravpundir231]

Hi All,

Thanks for your comments & advise

[Julio E. Moisa]

Hi

Some questions:

Is the switch configured with DHCP Snooping?,

is the SVI or Layer 3 interface configured with ip helper-address?

Sometime ti could be associated to a cable problem, the RJ45 is not properly added to the patch cord. 

[Georg Pauwen]

Hello,

in addition to the other posts, try:to configure your switch(es) with:

Switch(config)#no ip arp gratuitous

Also, if you want to keep clients from getting an APIPA address, you could configure an arp access list (below is an example):

arp access-list VLAN_10
permit ip 169.254.0.0 0.0.255.255 mac any
ip arp inspection filter VLAN_10 vlan 10