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DHCP snooping allowing DHCP without trust port

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Hulk8647
Level 1
Level 1

‎11-02-2017 07:47 AM - edited ‎03-08-2019 12:35 PM

Can anyone please help with this? This is out of the box switch. I have attached config. Nothing at all on it except vlan, dhcp snooping. I have configured NO dhcp trustport as you can see and I AM able to get IP for hosts. I'm lost with this. I tried "no ip dhcp snooping information option"and with the option, no difference. My host is sitting on port 6 and router on 10. Router is configured with dhcp pool. This is the most simplest config. Any ideas whats going on here?

map.png

 

TEST_TEST#sh run
Building configuration...

Current configuration : 1460 bytes
!
! Last configuration change at 14:42:27 UTC Thu Nov 2 2017
!
version 15.2
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname TEST_TEST
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
system mtu routing 1500
!
!
!
!
!
!
ip dhcp snooping vlan 1-4094 smartlog
no ip dhcp snooping information option
ip dhcp snooping
!
!
!
spanning-tree mode rapid-pvst
spanning-tree extend system-id
!
!
!
!
vlan internal allocation policy ascending
!
interface GigabitEthernet0/6
 description HOST
 switchport access vlan 100
 switchport mode access
 spanning-tree portfast edge
!
interface GigabitEthernet0/10
 description UPLINK
 switchport trunk allowed vlan 100
 switchport trunk native vlan 100
 switchport mode trunk
!
interface Vlan1
 no ip address
 shutdown
!
interface Vlan100
 ip address 10.90.9.253 255.255.255.0
 no ip route-cache
!
ip forward-protocol nd
ip http server
ip http secure-server
!
!
!
!
!
line con 0
line vty 5 15
!
!
end
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Hulk8647
Level 1
Level 1
In response to Georg Pauwen

‎11-02-2017 12:22 PM

Yes, it is in database.

 

I have finally figured it out. Took only 2 days but found the issue. The problem was on the windows machine. Something with windows auto-reconfiguring the same IP over and over despite the snooping enabled.

I have gotten another host non desktop/laptop and plugged it directly into the switch. Worked perfectly. Could not get an IP at all. Configured the switch port trust and I was able to get an IP. Removed the trust, turned the port off and ON, could not get an IP, added the trust again and got one!

 

This was not the case with the windows machine. Just to make this even more interesting, I excluded the dhcp IP address on the router that the laptop was constantly getting, saved my config, rebooted router, switch and PC, came back ON with the same IP which clearly tells me it's not properly using rotuers DHCP but somehow auto-configuring its own from the first time it received it.

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Hulk8647
Level 1
Level 1

‎11-02-2017 07:48 AM

here is additional info

TEST_TEST#sh ip dhcp snooping
Switch DHCP snooping is enabled
Switch DHCP gleaning is disabled
DHCP snooping is configured on following VLANs:
1-4094
DHCP snooping is operational on following VLANs:
1,100
Smartlog is configured on following VLANs:
1-4094
Smartlog is operational on following VLANs:
1,100
DHCP snooping is configured on the following L3 Interfaces:

Insertion of option 82 is disabled
   circuit-id default format: vlan-mod-port
   remote-id: ec1d.8bac.2d00 (MAC)
Option 82 on untrusted port is not allowed
Verification of hwaddr field is enabled
Verification of giaddr field is enabled
DHCP snooping trust/rate is configured on the following Interfaces:

Interface                  Trusted    Allow option    Rate limit (pps)
-----------------------    -------    ------------    ----------------


TEST_TEST#sh ip dhcp snooping statistics
 Packets Forwarded                                     = 27
 Packets Dropped                                       = 0
 Packets Dropped From untrusted ports                  = 0
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Georg Pauwen
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VIP

‎11-02-2017 08:30 AM

Hello,

 

what switch platform is this ? Can you enable 'feature dhcp' globally ?

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Hulk8647
Level 1
Level 1
In response to Georg Pauwen

‎11-02-2017 08:42 AM

yes I can enable dhcp service. Tried that too. No luck. I just enabled it though again

 

(C3560CX-UNIVERSALK9-M)

Version 15.2(4)E3

Also, I captured a debug of dhcp packets.

 

TEST_TEST#
Nov  2 15:36:41.468: %SYS-5-CONFIG_I: Configured from console by console
Nov  2 15:36:42.863: %LINK-3-UPDOWN: Interface GigabitEthernet0/6, changed state to down
Nov  2 15:36:45.400: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Gi0/6 for pak.  Was Vl100
Nov  2 15:36:45.400: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Vl100 for pak.  Was Gi0/6
Nov  2 15:36:45.404: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Gi0/6 for pak.  Was Vl100
Nov  2 15:36:45.404: DHCP_SNOOPING: received new DHCP packet from input interface (GigabitEthernet0/6)
Nov  2 15:36:45.404: DHCP_SNOOPING: process new DHCP packet, message type: DHCPREQUEST, input interface: Gi0/6,
TEST_TEST# MAC da: ffff.ffff.ffff, MAC sa: 507b.9d72.dfc4, 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: 507b.9d72.dfc4
Nov  2 15:36:45.404: DHCP_SNOOPING: message type : DHCPREQUEST 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: 507b.9d72.dfc4
Nov  2 15:36:45.404: DHCP_SNOOPING: add relay information option.
Nov  2 15:36:45.404: DHCP_SNOOPING_SW: encoding opt82 cid in vlan-mod-port format
Nov  2 15:36:45.404: DHCP_SNOOPING_SW: Encoding opt82 RID in MAC address format
Nov  2 15:36:45.404: DHCP_SNOOPING: binary dump of relay info option, length: 20 data:

Nov  2 15:36:45.404: DHCP_SNOOPING_SW: bridge packet get invalid mat entry: FFFF.FFFF.FFFF, packet is flooded to ingress VLAN: (100)
Nov  2 15:36:45.404: DHCP_SNOOPING_SW: bridge packet send packet to cpu port: Vlan100.
Nov  2 15:36:45.425: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Gi0/6 for pak.  Was Vl100
Nov  2 15:36:45.425: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Vl100 for pak.  Was Gi0/6
Nov  2 15:36:45.425: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Gi0/6 for pak.  Was Vl100
Nov  2 15:36:45.425: DHCP_SNOOPING: received new DHCP packet from input interface (GigabitEthernet0/6)
Nov  2 15:36:45.425: DHCP_SNOOPING: process new DHCP packet, message type: DHCPREQUEST, input interface: Gi0/6, MAC da: ffff.ffff.ffff, MAC sa: 507b.9d72.dfc4, 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: 507b.9d72.dfc4
Nov  2 15:36:45.425: DHCP_SNOOPING: message type : DHCPREQUEST 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: 507b.9d72.dfc4
Nov  2 15:36:45.425: DHCP_SNOOPING: add relay information option.
Nov  2 15:36:45.425: DHCP_SNOOPING_SW: encoding opt82 cid in vlan-mod-port format
Nov  2 15:36:45.425: DHCP_SNOOPING_SW: Encoding opt82 RID in MAC address format
Nov  2 15:36:45.425: DHCP_SNOOPING: binary dump of relay info option, length: 20 data:

Nov  2 15:36:45.428: DHCP_SNOOPING_SW: bridge packet get invalid mat entry: FFFF.FFFF.FFFF, packet is flooded to ingress VLAN: (100)
Nov  2 15:36:45.428: DHCP_SNOOPING_SW: bridge packet send packet to cpu port: Vlan100.
Nov  2 15:36:47.337: %LINK-3-UPDOWN: Interface GigabitEthernet0/6, changed state to up
Nov  2 15:36:48.340: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/6, changed state to up
Nov  2 15:36:48.497: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Gi0/6 for pak.  Was Vl100
Nov  2 15:36:48.497: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Vl100 for pak.  Was Gi0/6
Nov  2 15:36:48.497: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Gi0/6 for pak.  Was Vl100
Nov  2 15:36:48.497: DHCP_SNOOPING: received new DHCP packet from input interface (GigabitEthernet0/6)
Nov  2 15:36:48.497: DHCP_SNOOPING: process new DHCP packet, message type: DHCPREQUEST, input interface: Gi0/6, MAC da: ffff.ffff.ffff, MAC sa: 507b.9d72.dfc4, 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: 507b.9d72.dfc4
Nov  2 15:36:48.497: DHCP_SNOOPING: message type : DHCPREQUEST 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: 507b.9d72.dfc4
Nov  2 15:36:48.497: DHCP_SNOOPING: add relay information option.
Nov  2 15:36:48.497: DHCP_SNOOPING_SW: encoding opt82 cid in vlan-mod-port format
Nov  2 15:36:48.497: DHCP_SNOOPING_SW: Encoding opt82 RID in MAC address format
Nov  2 15:36:48.497: DHCP_SNOOPING: binary dump of relay info option, length: 20 data:

Nov  2 15:36:48.497: DHCP_SNOOPING_SW: bridge packet get invalid mat entry: FFFF.FFFF.FFFF, packet is flooded to ingress VLAN: (100)
Nov  2 15:36:48.501: DHCP_SNOOPING_SW: bridge packet send packet to cpu port: Vlan100.
Nov  2 15:36:54.663: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Gi0/6 for pak.  Was Vl100
Nov  2 15:36:54.666: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Vl100 for pak.  Was Gi0/6
Nov  2 15:36:54.666: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Gi0/6 for pak.  Was Vl100
Nov  2 15:36:54.666: DHCP_SNOOPING: received new DHCP packet from input interface (GigabitEthernet0/6)
Nov  2 15:36:54.666: DHCP_SNOOPING: process new DHCP packet, message type: DHCPREQUEST, input interface: Gi0/6, MAC da: ffff.ffff.ffff, MAC sa: 507b.9d72.dfc4, 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: 507b.9d72.dfc4
Nov  2 15:36:54.666: DHCP_SNOOPING: message type : DHCPREQUEST 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: 507b.9d72.dfc4
Nov  2 15:36:54.666: DHCP_SNOOPING: add relay information option.
Nov  2 15:36:54.666: DHCP_SNOOPING_SW: encoding opt82 cid in vlan-mod-port format
Nov  2 15:36:54.666: DHCP_SNOOPING_SW: Encoding opt82 RID in MAC address format
Nov  2 15:36:54.666: DHCP_SNOOPING: binary dump of relay info option, length: 20 data:

Nov  2 15:36:54.666: DHCP_SNOOPING_SW: bridge packet get invalid mat entry: FFFF.FFFF.FFFF, packet is flooded to ingress VLAN: (100)
Nov  2 15:36:54.666: DHCP_SNOOPING_SW: bridge packet send packet to cpu port: Vlan100.
TEST_TEST#
Nov  2 15:37:11.618: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Gi0/6 for pak.  Was Vl100
Nov  2 15:37:11.618: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Vl100 for pak.  Was Gi0/6
Nov  2 15:37:11.618: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Gi0/6 for pak.  Was Vl100
Nov  2 15:37:11.618: DHCP_SNOOPING: received new DHCP packet from input interface (GigabitEthernet0/6)
Nov  2 15:37:11.618: DHCP_SNOOPING: process new DHCP packet, message type: DHCPREQUEST, input interface: Gi0/6,u   MAC da: ffff.ffff.ffff, MAC sa: 507b.9d72.dfc4, 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: 507b.9d72.dfc4
Nov  2 15:37:11.618: DHCP_SNOOPING: message type : DHCPREQUEST 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: 507b.9d72.dfc4
Nov  2 15:37:11.618: DHCP_SNOOPING: add relay information option.
Nov  2 15:37:11.618: DHCP_SNOOPING_SW: encoding opt82 cin vlan-mod-port format
Nov  2 15:37:11.618: DHCP_SNOOPING_SW: Encoding opt82 RID in MAC address format
Nov  2 15:37:11.618: DHCP_SNOOPING: binary dump of relay info option, length: 20 data:

Nov  2 15:37:11.622: DHCP_SNOOPING_SW: bridge packet get invalid mat entry: FFFF.FFFF.FFFF, packet is flooded to ingress VLAN: (100)
Nov  2 15:37:11.622: DHCP_SNOOPING_SW: bridge packet send packet to cpu port: Vlan100.
Nov  2 15:37:15.736: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Gi0/6 for pak.  Was Vl100
Nov  2 15:37:15.736: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Vl100 for pak.  Was Gi0/6
Nov  2 15:37:15.736: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Gi0/6 for pak.  Was Vl100
Nov  2 15:37:15.736: DHCP_SNOOPING: received new DHCP packet from input interface (GigabitEthernet0/6)
Nov  2 15:37:15.736: DHCP_SNOOPING: process new DHCP packet, message type: DHCPREQUEST, input interface: Gi0/6, MAC da: ffff.ffff.ffff, MAC sa: 507b.9d72.dfc4, 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: 507b.9d72.dfc4
Nov  2 15:37:15.736: DHCP_SNOOPING: message type : DHCPREQUEST 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: 507b.9d72.dfc4
Nov  2 15:37:15.736: DHCP_SNOOPING: add relay information option.
Nov  2 15:37:15.736: DHCP_SNOOPING_SW: encoding opt82 cid in vlan-mod-port format
Nov  2 15:37:15.736: DHCP_SNOOPING_SW: Encoding opt82 RID in MAC address format
Nov  2 15:37:15.736: DHCP_SNOOPING: binary dump of relay info option, length: 20 data:

Nov  2 15:37:15.739: DHCP_SNOOPING_SW: bridge packet get invalid mat entry: FFFF.FFFF.FFFF, packet is flooded to ingress VLAN: (100)
Nov  2 15:37:15.739: DHCP_SNOOPING_SW: bridge packet send packet to cpu port: Vlan100.
Nov  2 15:37:22.845: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Gi0/6 for pak.  Was Vl100
Nov  2 15:37:22.845: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Vl100 for pak.  Was Gi0/6
Nov  2 15:37:22.845: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Gi0/6 for pak.  Was Vl100
Nov  2 15:37:22.845: DHCP_SNOOPING: received new DHCP packet from input interface (GigabitEthernet0/6)
Nov  2 15:37:22.849: DHCP_SNOOPING: process new DHCP packet, message type: DHCPREQUEST, input interface: Gi0/6, MAC da: ffff.ffff.ffff, MAC sa: 507b.9d72.dfc4, 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: 507b.9d72.dfc4
Nov  2 15:37:22.849: DHCP_SNOOPING: message type : DHCPREQUEST 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: 507b.9d72.dfc4
Nov  2 15:37:22.849: DHCP_SNOOPING: add relay information option.
Nov  2 15:37:22.849: DHCP_SNOOPING_SW: encoding opt82 cid in vlan-mod-port format
Nov  2 15:37:22.849: DHCP_SNOOPING_SW: Encoding opt82 RID in MAC address format
Nov  2 15:37:22.849: DHCP_SNOOPING: binary dump of relay info option, length: 20 data:

Nov  2 15:37:22.849: DHCP_SNOOPING_SW: bridge packet get invalid mat entry: FFFF.FFFF.FFFF, packet is flooded to ingress VLAN: (100)
Nov  2 15:37:22.849: DHCP_SNOOPING_SW: bridge packet send packet to cpu port: Vlan100.
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Hulk8647
Level 1
Level 1
In response to Hulk8647

‎11-02-2017 08:46 AM

from the debugs, it looks like im not getting any ip, im not sure why i am though
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Hulk8647
Level 1
Level 1
In response to Hulk8647

‎11-02-2017 08:50 AM

never mind, the message just came in

Nov  2 15:49:58.288: DHCP_SNOOPING_SW: bridge packet get invalid mat entry: FFFF.FFFF.FFFF, packet is flooded to ingress VLAN: (100)
Nov  2 15:49:58.288: DHCP_SNOOPING_SW: bridge packet send packet to cpu port: Vlan100.
Nov  2 15:50:03.276: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Gi0/6 for pak.  Was Vl100
Nov  2 15:50:03.276: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Vl100 for pak.  Was Gi0/6
Nov  2 15:50:03.276: DHCPSNOOP(hlfm_set_if_input): Setting if_input to Gi0/6 for pak.  Was Vl100
Nov  2 15:50:03.276: DHCP_SNOOPING: received new DHCP packet from input interface (GigabitEthernet0/6)
Nov  2 15:50:03.279: DHCP_SNOOPING: process new DHCP packet, message type: DHCPINFORM, input interface: Gi0/6, MAC da: ffff.ffff.ffff, MAC sa: 507b.9d72.dfc4, IP da: 255.255.255.255, IP sa: 10.90.9.52, DHCP ciaddr: 10.90.9.52, DHCP yiaddr: 0.0.0.0, DHCP siaddr: 0.0.0.0, DHCP giaddr: 0.0.0.0, DHCP chaddr: 507b.9d72.dfc4
Nov  2 15:50:03.279: DHCP_SNOOPING: message type : DHCPINFORM DHCP ciaddr: 10.90.9.52, DHCP yiaddr: 0.0.0.0, DHCP siaddr: 0.0.0.0, DHCP giaddr: 0.0.0.0, DHCP chaddr: 507b.9d72.dfc4
Nov  2 15:50:03.279: DHCP_SNOOPING: add relay information option.
Nov  2 15:50:03.279: DHCP_SNOOPING_SW: encoding opt82 cid in vlan-mod-port format
Nov  2 15:50:03.279: DHCP_SNOOPING_SW: Encoding opt82 RID in MAC address format
Nov  2 15:50:03.279: DHCP_SNOOPING: binary dump of relay info option, length: 20 data:
Nov  2 15:50:03.279: 0x52
Nov  2 15:50:03.279: 0x12
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Georg Pauwen
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VIP
In response to Hulk8647

‎11-02-2017 08:51 AM - edited ‎11-02-2017 08:52 AM

Hello,

 

according to the feature navigator, for the 3560CX with 15.2(4)E3 you need at least IP Base or IP Services. Check if you might be running just the LAN Base image (show license all)...

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Hulk8647
Level 1
Level 1
In response to Georg Pauwen

‎11-02-2017 08:53 AM 

TEST_TEST#sh license all
License Store: Primary License Storage
License Store: Built-In License Storage
StoreIndex: 0   Feature: ipservices                        Version: 1.0
        License Type: Evaluation
        License State: Active, Not in Use, EULA not accepted
            Evaluation total period: 12 weeks 6  days
            Evaluation period left: 12 weeks 6  days
            Period used: 0  minute  0  second
        License Priority: None
        License Count: Non-Counted

StoreIndex: 1   Feature: ipservices                        Version: 1.0
        License Type: PermanentRightToUse
        License State: Inactive
            Period used: 0  minute  0  second
        License Priority: None
        License Count: Non-Counted
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Georg Pauwen
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In response to Hulk8647

‎11-02-2017 09:21 AM

You are running IP Services (the evaluation version, don't forget to accept the EULA), so that should be fine...

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Hulk8647
Level 1
Level 1
In response to Georg Pauwen

‎11-02-2017 09:47 AM

i just tried accepting and i did not work looks like.

I tried these two and rebooted:

license right-to-use activate ipservices evaluation
license right-to-use activate ipservices acceptEULA

 

After reboot:

TEST_TEST#sh license all
License Store: Primary License Storage
License Store: Built-In License Storage
StoreIndex: 0   Feature: ipservices                        Version: 1.0
        License Type: Evaluation
        License State: Inactive
            Evaluation total period: 12 weeks 6  days
            Evaluation period left: 12 weeks 6  days
            Period used: 0  minute  0  second
        License Priority: None
        License Count: Non-Counted

StoreIndex: 1   Feature: ipservices                        Version: 1.0
        License Type: PermanentRightToUse
        License State: Active, In Use
            Period used: 1  minute  35 seconds
        License Priority: High
        License Count: Non-Counted
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Hulk8647
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In response to Hulk8647

‎11-02-2017 09:56 AM

either way, it's not working. (dhcp snooping that is)
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Georg Pauwen
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In response to Hulk8647

‎11-02-2017 11:27 AM - edited ‎11-02-2017 11:28 AM

Hello,

 

is VLAN 100 actually in your VLAN database ? Did you create it in config mode:

 

Switch(config)#vlan 100 

 

?

 

Also, can you post the configuration of the router that serves as the DHCP server ?

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Hulk8647
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In response to Georg Pauwen

‎11-02-2017 12:22 PM

Yes, it is in database.

 

I have finally figured it out. Took only 2 days but found the issue. The problem was on the windows machine. Something with windows auto-reconfiguring the same IP over and over despite the snooping enabled.

I have gotten another host non desktop/laptop and plugged it directly into the switch. Worked perfectly. Could not get an IP at all. Configured the switch port trust and I was able to get an IP. Removed the trust, turned the port off and ON, could not get an IP, added the trust again and got one!

 

This was not the case with the windows machine. Just to make this even more interesting, I excluded the dhcp IP address on the router that the laptop was constantly getting, saved my config, rebooted router, switch and PC, came back ON with the same IP which clearly tells me it's not properly using rotuers DHCP but somehow auto-configuring its own from the first time it received it.

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Georg Pauwen
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In response to Hulk8647

‎11-02-2017 12:47 PM

Interesting. What happens if you stop/start the DHCP Client service on the Windows machine ?

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Hulk8647
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Level 1
In response to Georg Pauwen

‎11-02-2017 12:52 PM

i haven't played with the laptop windows config yet. Will definitely look into it. I also got other hots for testing and making sure that this is the issue and all came out OK. It is strange and obviously a pretty big issue if you're implementing snooping. Something to pay attention too
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