DHCP on switch 169 addresses

[Bob Greer]

Hi there,

Thanks for reading!

We have wireless clients that are getting 169 addresses.  We've pushed the DHCP process to the access layer switches where APs are plugged into.  One AP/switch gives clients valid IP addresses but the other doesn't.  See attachment for diagram.

Here's a sample error from a client:

Nov 29 19:15:21.250: DHCP_SNOOPING: process new DHCP packet, message type: DHCPDISCOVER, input interface: Gi0/1, MAC da: ffff.ffff.ffff, MAC sa: 3441.5df9.0353, IP da: 255.255.255.255, IP sa: 0.0.0.0, DHCP ciaddr: 0.0.0.0, DHCP yiaddr: 0.0.0.0, DHCP siaddr: 0.0.0.0, DHCP giaddr: 0.0.0.0, DHCP chaddr: 3441.5df9.0353
Nov 29 19:15:21.250: DHCP_SNOOPING_SW: bridge packet get invalid mat entry: FFFF.FFFF.FFFF, packet is flooded to ingress VLAN: (244)

Thanks!

Bob

[balaji.bandi]

in your diagram, which one working and which one not working,

can you post Sw1 trunk port configuration, also please post working and  not working switch configuration

[Bob Greer]

Hi BB, thanks for writing!

The two trunk ports are one line only:
switchport mode trunk

The bottom switch (sw04) has the working configuration.  sw03 is broken.  I've attached running configs

Thanks again,

Bob

[balaji.bandi]

If you compare the configuration the SW3, SW3  do not have VLAN created, make sure you set also vtp mode a transparent.

DHCP  exclude do not match, Cross check again all the config line by line.

[Bob Greer]

Thanks again for writing!

As you can see from the naming, it's all temporary deploys until permanent configurations. The exclude statement is a kluge. It's an attempt to manually prevent IP dups while still leaving the VSI on the router visible.

I saw that about sw03: no vlans in config. I added them, ran show config, and they don't appear. They DO appear in show vlan and in fact you can see port assignments:
swmx003_TEMP# show vlan

VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0/5, Fa0/9, Fa0/10, Fa0/11
Fa0/12, Fa0/13, Fa0/14, Fa0/16
Fa0/22, Gi0/2
111 management active
130 server active
132 RC-Cards active
133 VoiceGateway-1 active
134 printer active
136 Facility-Management active
137 time-logging active
138 Security_Cameras active
140 Production active
144 officepc active
161 VLAN0161 active
168 ProductionServer active Fa0/1, Fa0/4, Fa0/6, Fa0/7
Fa0/8, Fa0/18, Fa0/19, Fa0/24
169 ZebraPr ProdAux active Fa0/2, Fa0/15, Fa0/17, Fa0/20
Fa0/21, Fa0/23
236 guest_WiFi active
238 Wlan-ap-capwap active
244 officepc-wifi active
249 Backup-remote-NDMP active
250 VMWare-FT-VMotion active
251 VMWare-ISCSI active

[Georg Pauwen]

Hello,

on a side note, on your sw03, the system mtu routing is set to 1504. This is usually configured for QinQ. Try and change it to 1500:

system mtu routing 1500

Also, your sw04 is in VTP Transparent mode. Set both switches to 'vtp mode server' (sw03 probably already is, since 'server' is the default)...