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Occasional Contributor II
Posts: 15
Registered: ‎03-27-2013

Local Controller doesn't allow Client DHCP

Customer has a pair of MCs, Master-Local.

EAP-authenticated SSID.  Clients that associate to APs on the Master MC authentcate, and get an IP address from the external DHCP server.  Clients that associate to the APs on the Local MC cannot get an IP from DHCP. THese clients must go through some sort of auth as they show a User Role of Authenticated, but an IP address of 0.0.0.0.  Both MCs are on the same subnet.  S/W 6.4.3.3

Usual things like switchport config, allowed VLANs, etc checked.

Suggestions?

thanks in advance.

Valued Contributor II
Posts: 804
Registered: ‎12-01-2014

Re: Local Controller doesn't allow Client DHCP

HI,

 

Here we need to check couple of things,

 

1. Whether the user VLAN is created and having an IP address on that VLAN interface ?

2. If the DHCP is configured externally, is the IP-Helper configured on the user VLAN interface ?

 

If possible please share the output of the following,

1. show user-table

2. show ip route

3. show ip interface VLAN <user vlan id>

 

 

We can easily figure out the issue.

Cheers,
Venu Puduchery,
[Is my post helped you ? Give Kudos :) ]
Occasional Contributor II
Posts: 15
Registered: ‎03-27-2013

Re: Local Controller doesn't allow Client DHCP

Thanks  alot for the information.

The master MC doesn't have a VLAN interface, or IP helper and it gets DHCP from the external server fine.

I gave the VLAN an IP, and added the helper to the DHCP server, and clients still don't get an IP.

Here is the debug result after setting logging level debug network subcat dhcp. The information at 6:46am is before the IP helper was added, the info at 7:45 after.  neither scenario gave client DHCP.

Sep 3 06:46:51 :202541:  <DBUG> |dhcpdwrap| |dhcp| Received DHCP packet from Datpath, sos msg hdr flags 0x40 opcode 0x5a ingress 0x10010 vlan 37 egress 0x0 src mac 70:f1:a1:88:24:be
Sep 3 06:46:51 :202534:  <DBUG> |dhcpdwrap| |dhcp| Datapath vlan37: DISCOVER 70:f1:a1:88:24:be Transaction ID:0xb606e20e Options 3d:0170f1a18824be 0c:4b2d4c2d3334343230 3c:4d53465420352e30 37:010f03062c2e2f1f2179f92b
Sep 3 06:46:55 :202541:  <DBUG> |dhcpdwrap| |dhcp| Received DHCP packet from Datpath, sos msg hdr flags 0x40 opcode 0x5a ingress 0x10010 vlan 37 egress 0x0 src mac 70:f1:a1:88:24:be
Sep 3 06:46:55 :202534:  <DBUG> |dhcpdwrap| |dhcp| Datapath vlan37: DISCOVER 70:f1:a1:88:24:be Transaction ID:0xb606e20e Options 3d:0170f1a18824be 0c:4b2d4c2d3334343230 3c:4d53465420352e30 37:010f03062c2e2f1f2179f92b
Sep 3 07:44:24 :202541:  <DBUG> |dhcpdwrap| |dhcp| Received DHCP packet from Datpath, sos msg hdr flags 0x40 opcode 0x5a ingress 0x1000d vlan 21 egress 0x0 src mac 38:aa:3c:20:64:3b
Sep 3 07:44:24 :202534:  <DBUG> |dhcpdwrap| |dhcp| Datapath vlan21: DISCOVER 38:aa:3c:20:64:3b Transaction ID:0x5d60b8d7 Options 3d:0138aa3c20643b 39:05dc 3c:6468637063642d352e322e31303a4c696e75782d332e302e382d32303132303831342e3130303531332d757365723a61726d76376c3a53414d53554e47204d325f415454 0c:616e64726f69642d34643636303263653730323634656337 37:012103060f1c333a3b
Sep 3 07:44:28 :202541:  <DBUG> |dhcpdwrap| |dhcp| Received DHCP packet from Datpath, sos msg hdr flags 0x40 opcode 0x5a ingress 0x1000d vlan 21 egress 0x15 src mac 38:aa:3c:20:64:3b
Sep 3 07:44:28 :202534:  <DBUG> |dhcpdwrap| |dhcp| Datapath vlan21: DISCOVER 38:aa:3c:20:64:3b Transaction ID:0x5d60b8d7 Options 3d:0138aa3c20643b 39:05dc 3c:6468637063642d352e322e31303a4c696e75782d332e302e382d32303132303831342e3130303531332d757365723a61726d76376c3a53414d53554e47204d325f415454 0c:616e64726f69642d34643636303263653730323634656337 37:012103060f1c333a3b
Sep 3 07:44:28 :202523:  <DBUG> |dhcpdwrap| |dhcp| dhcprelay: dev=eth1, length=364, from_port=68, op=1, giaddr=0.0.0.0
Sep 3 07:44:28 :202532:  <DBUG> |dhcpdwrap| |dhcp| got 1 relay servers
Sep 3 07:44:28 :202533:  <DBUG> |dhcpdwrap| |dhcp| Relayed: DISCOVER server=142.23.95.1 giaddr=10.1.160.2 MAC=38:aa:3c:20:64:3b
Sep 3 07:44:28 :202541:  <DBUG> |dhcpdwrap| |dhcp| Received DHCP packet from Datpath, sos msg hdr flags 0x42 opcode 0x5a ingress 0x0 vlan 1 egress 0x2100 src mac 00:0b:86:b7:56:d7
Sep 3 07:44:28 :202534:  <DBUG> |dhcpdwrap| |dhcp| Datapath vlan1: DISCOVER 38:aa:3c:20:64:3b Transaction ID:0x5d60b8d7 Options 3d:0138aa3c20643b 39:05dc 3c:6468637063642d352e322e31303a4c696e75782d332e302e382d32303132303831342e3130303531332d757365723a61726d76376c3a53414d53554e47204d325f415454 0c:616e64726f69642d34643636303263653730323634656337 37:012103060f1c333a3b
Sep 3 07:44:28 :202523:  <DBUG> |dhcpdwrap| |dhcp| dhcprelay: dev=eth1, length=364, from_port=67, op=1, giaddr=10.1.160.2
Sep 3 07:44:37 :202541:  <DBUG> |dhcpdwrap| |dhcp| Received DHCP packet from Datpath, sos msg hdr flags 0x40 opcode 0x5a ingress 0x1000d vlan 21 egress 0x15 src mac 38:aa:3c:20:64:3b
Sep 3 07:44:37 :202534:  <DBUG> |dhcpdwrap| |dhcp| Datapath vlan21: DISCOVER 38:aa:3c:20:64:3b Transaction ID:0x5d60b8d7 Options 3d:0138aa3c20643b 39:05dc 3c:6468637063642d352e322e31303a4c696e75782d332e302e382d32303132303831342e3130303531332d757365723a61726d76376c3a53414d53554e47204d325f415454 0c:616e64726f69642d34643636303263653730323634656337 37:012103060f1c333a3b
Sep 3 07:44:37 :202523:  <DBUG> |dhcpdwrap| |dhcp| dhcprelay: dev=eth1, length=364, from_port=68, op=1, giaddr=0.0.0.0
Sep 3 07:44:37 :202532:  <DBUG> |dhcpdwrap| |dhcp| got 1 relay servers
Sep 3 07:44:37 :202533:  <DBUG> |dhcpdwrap| |dhcp| Relayed: DISCOVER server=142.23.95.1 giaddr=10.1.160.2 MAC=38:aa:3c:20:64:3b
Sep 3 07:44:37 :202541:  <DBUG> |dhcpdwrap| |dhcp| Received DHCP packet from Datpath, sos msg hdr flags 0x42 opcode 0x5a ingress 0x0 vlan 1 egress 0x2100 src mac 00:0b:86:b7:56:d7
Sep 3 07:44:37 :202534:  <DBUG> |dhcpdwrap| |dhcp| Datapath vlan1: DISCOVER 38:aa:3c:20:64:3b Transaction ID:0x5d60b8d7 Options 3d:0138aa3c20643b 39:05dc 3c:6468637063642d352e322e31303a4c696e75782d332e302e382d32303132303831342e3130303531332d757365723a61726d76376c3a53414d53554e47204d325f415454 0c:616e64726f69642d34643636303263653730323634656337 37:012103060f1c333a3b
Sep 3 07:44:37 :202523:  <DBUG> |dhcpdwrap| |dhcp| dhcprelay: dev=eth1, length=364, from_port=67, op=1, giaddr=10.1.160.2
Sep 3 07:44:53 :202541:  <DBUG> |dhcpdwrap| |dhcp| Received DHCP packet from Datpath, sos msg hdr flags 0x40 opcode 0x5a ingress 0x1000d vlan 21 egress 0x15 src mac 38:aa:3c:20:64:3b
Sep 3 07:44:53 :202534:  <DBUG> |dhcpdwrap| |dhcp| Datapath vlan21: DISCOVER 38:aa:3c:20:64:3b Transaction ID:0x5d60b8d7 Options 3d:0138aa3c20643b 39:05dc 3c:6468637063642d352e322e31303a4c696e75782d332e302e382d32303132303831342e3130303531332d757365723a61726d76376c3a53414d53554e47204d325f415454 0c:616e64726f69642d34643636303263653730323634656337 37:012103060f1c333a3b
Sep 3 07:44:53 :202523:  <DBUG> |dhcpdwrap| |dhcp| dhcprelay: dev=eth1, length=364, from_port=68, op=1, giaddr=0.0.0.0
Sep 3 07:44:53 :202532:  <DBUG> |dhcpdwrap| |dhcp| got 1 relay servers
Sep 3 07:44:53 :202533:  <DBUG> |dhcpdwrap| |dhcp| Relayed: DISCOVER server=142.23.95.1 giaddr=10.1.160.2 MAC=38:aa:3c:20:64:3b
Sep 3 07:44:53 :202541:  <DBUG> |dhcpdwrap| |dhcp| Received DHCP packet from Datpath, sos msg hdr flags 0x42 opcode 0x5a ingress 0x0 vlan 1 egress 0x2100 src mac 00:0b:86:b7:56:d7
Sep 3 07:44:53 :202534:  <DBUG> |dhcpdwrap| |dhcp| Datapath vlan1: DISCOVER 38:aa:3c:20:64:3b Transaction ID:0x5d60b8d7 Options 3d:0138aa3c20643b 39:05dc 3c:6468637063642d352e322e31303a4c696e75782d332e302e382d32303132303831342e3130303531332d757365723a61726d76376c3a53414d53554e47204d325f415454 0c:616e64726f69642d34643636303263653730323634656337 37:012103060f1c333a3b
Sep 3 07:44:53 :202523:  <DBUG> |dhcpdwrap| |dhcp| dhcprelay: dev=eth1, length=364, from_port=67, op=1, giaddr=10.1.160.2
Sep 3 07:45:00 :202541:  <DBUG> |dhcpdwrap| |dhcp| Received DHCP packet from Datpath, sos msg hdr flags 0x40 opcode 0x5a ingress 0x1000d vlan 21 egress 0x0 src mac 38:aa:3c:20:64:3b
Sep 3 07:45:00 :202534:  <DBUG> |dhcpdwrap| |dhcp| Datapath vlan21: DISCOVER 38:aa:3c:20:64:3b Transaction ID:0x1032bac0 Options 3d:0138aa3c20643b 39:05dc 3c:6468637063642d352e322e31303a4c696e75782d332e302e382d32303132303831342e3130303531332d757365723a61726d76376c3a53414d53554e47204d325f415454 0c:616e64726f69642d34643636303263653730323634656337 37:012103060f1c333a3b
Sep 3 07:45:05 :202541:  <DBUG> |dhcpdwrap| |dhcp| Received DHCP packet from Datpath, sos msg hdr flags 0x40 opcode 0x5a ingress 0x1000d vlan 21 egress 0x15 src mac 38:aa:3c:20:64:3b
Sep 3 07:45:05 :202534:  <DBUG> |dhcpdwrap| |dhcp| Datapath vlan21: DISCOVER 38:aa:3c:20:64:3b Transaction ID:0x1032bac0 Options 3d:0138aa3c20643b 39:05dc 3c:6468637063642d352e322e31303a4c696e75782d332e302e382d32303132303831342e3130303531332d757365723a61726d76376c3a53414d53554e47204d325f415454 0c:616e64726f69642d34643636303263653730323634656337 37:012103060f1c333a3b
Sep 3 07:45:05 :202523:  <DBUG> |dhcpdwrap| |dhcp| dhcprelay: dev=eth1, length=364, from_port=68, op=1, giaddr=0.0.0.0
Sep 3 07:45:05 :202532:  <DBUG> |dhcpdwrap| |dhcp| got 1 relay servers
Sep 3 07:45:05 :202533:  <DBUG> |dhcpdwrap| |dhcp| Relayed: DISCOVER server=142.23.95.1 giaddr=10.1.160.2 MAC=38:aa:3c:20:64:3b
Sep 3 07:45:05 :202523:  <DBUG> |dhcpdwrap| |dhcp| dhcprelay: dev=eth1, length=364, from_port=67, op=1, giaddr=10.1.160.2
Sep 3 07:45:05 :202541:  <DBUG> |dhcpdwrap| |dhcp| Received DHCP packet from Datpath, sos msg hdr flags 0x42 opcode 0x5a ingress 0x0 vlan 1 egress 0x2100 src mac 00:0b:86:b7:56:d7
Sep 3 07:45:05 :202534:  <DBUG> |dhcpdwrap| |dhcp| Datapath vlan1: DISCOVER 38:aa:3c:20:64:3b Transaction ID:0x1032bac0 Options 3d:0138aa3c20643b 39:05dc 3c:6468637063642d352e322e31303a4c696e75782d332e302e382d32303132303831342e3130303531332d757365723a61726d76376c3a53414d53554e47204d325f415454 0c:616e64726f69642d34643636303263653730323634656337 37:012103060f1c333a3b

 

Valued Contributor II
Posts: 804
Registered: ‎12-01-2014

Re: Local Controller doesn't allow Client DHCP

HI,

 

Following is the workaround to diagnose the issue,

 

1. Check which VLAN users are falling into ? show station table / show user-table

2. Check whether the Local controller is having the user VLAN and status is UP ? show vlan and show ip interface brief (most of the time we will forget issue the command, "operstate up" on the VLAN interface)

3. Ensure you can PING DHCP from the local controller . ping <DHCP IP>

4. Ensure that you have ip-helper address configured on the user VLAN interface.

 

Please feel free for any further help on this.

 

Cheers,
Venu Puduchery,
[Is my post helped you ? Give Kudos :) ]
Occasional Contributor II
Posts: 15
Registered: ‎03-27-2013

Re: Local Controller doesn't allow Client DHCP

Hello,

It turns out the customer had a routing/switching issue on their LAN.  Once that was tracked down and corrected, everything works.

Thanks so much for the replies.

 

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