DHCP issue with WS-C3560G-24PS

Unanswered Question
Sep 28th, 2011
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Hi ,


DHCP relay not working in switch WS-C3560G-24PS


image details -

c3560-ipservicesk9-mz.122-55.SE.bin


its working if i keep DHCP server in same vlan as user ., wireshark says DHCP offer packets are currupted and there is no client ip (0.0.0.0 0.0.0.0 ) .


shark.jpeg


Thanks 4 reply

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cadet alain Thu, 09/29/2011 - 00:57
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Hi,


Could you post the wireshark capture file filtering only DHCP.

Provide sh run | s dhcp.

Also do a debug ip dhcp server events and debug ip dhcp server packets on the switch doing relay.


Regards.


Alain.

shehinpm1 Thu, 09/29/2011 - 01:45
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Hi saqar,


i hope u hv configured "ip helper-address" in all other vlan interfaces.



Thx


shehin.pm

cadet alain Thu, 09/29/2011 - 06:54
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Hi,


I was talking about the modified pcap showing only dhcp not a screenshot.

Can you also picture your topology with HSRP, DHCP server, DHCP pools and provide output of sh run | be dhcp on the switch.

Where was the capture taken? where is located DHCP server, is it router, w2k3,linux?


Regards.


Alain.

Mukund M Deshpande Thu, 09/29/2011 - 07:19
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Hi Alain ,


This is windows server , switch 3560 acting as relay .Before switch was working as IOS DHCP and now I want it to configure as relay agent only .


In same vlan its working fine but on diff vlans its not .


I m not able to attach wireshark capture here , not able to find option   what most i can say DHCP offer packet is currupt with 0.0.0.0 in client address .


please let me know if any thing you can suggest me .


Thanks 4 reply

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cadet alain Thu, 09/29/2011 - 07:40
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Hi,


provide a picture of topology and post running of the 3560 .


Just use the attached file at the bottom of window to attach pcap file.


Regards.


Alain.

Mukund M Deshpande Thu, 09/29/2011 - 11:13
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Hi Alain ,


            wireshark attached 4 during the issue .


           topology is simple as both server and clients connected on same switch which is working as relay between two vlans .


Thanks 4 ur early repluy

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Mukund M Deshpande Thu, 09/29/2011 - 11:17
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foget to add - full config I m not able to past here but here is the vlan for which i did wireshark capture -


!

interface Vlan100

description <<< A_Corp >>>

ip vrf forwarding A_VRF

ip address 10.107.170.2 255.255.255.192

ip access-group A_Corp in

ip helper-address 10.107.170.228

no ip redirects

no ip unreachables

no ip proxy-arp

standby 100 ip 10.107.170.1

standby 100 timers 5 10

standby 100 preempt

standby 100 authentication md5 key-string 7 052D423960666E3039

!

cadet alain Thu, 09/29/2011 - 13:32
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Hi,


I've never configured DHCP relay agent with vrf so I'll lab it up to see if this is the vrf which may be causing the problem.



Regards.


Alain

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