Dhcp snooping shows 0.0.0.0 in one vlan

[dil_szczecin1]

Hello 

I started with dhcp snooping in my network. I got 4 Vlans 10,30,221,250. Dhcp snooping shows fine in 2 vlans :

MAC Address IP Address Lease (sec) Type VLAN Interface
------------------ --------------- ------------ ---------- ---- ----------
64:00:6a:2d:27:1c 172.28.0.174 3300 learned 22 gi45
64:00:6a:2d:8a:3c 172.28.0.140 3331 learned 22 gi38
b8:ac:6f:9b:44:a0 172.28.0.168 3303 learned 22 gi37

a4:ba:db:f8:f6:db 172.28.1.149 30147 learned 250 gi13

but problem is with vlan 221, dhcp is not showing and not binding any ip. I saw only something like that :

MAC Address IP Address Lease (sec) Type VLAN Interface
------------------ --------------- ------------ ---------- ---- ----------
64:00:6a:2d:27:1c 172.28.0.174 3112 learned 22 gi45
64:00:6a:2d:8a:3c 172.28.0.140 3143 learned 22 gi38
b8:ac:6f:9b:44:a0 172.28.0.168 3115 learned 22 gi37

a4:ba:db:f8:f6:db 172.28.1.149 30147 learned 250 gi13
64:00:6a:2d:8b:a9 0.0.0.0 108 learned 221 gi2

lease time counting to 0 and mac with 0 ip dissaper. I can't fire ip source guard because dhcp snooping is killing 

everything in vlan221.

My config for dhcp snooping is simple :

ip dhcp snooping
ip dhcp snooping database
ip dhcp snooping vlan 10
ip dhcp snooping vlan 30
ip dhcp snooping vlan 221
ip dhcp snooping vlan 250

What's happening with vlan 221? 

[paul driver]

---

@dil_szczecin1 wrote:

Hello 

I started with dhcp snooping in my network. I got 4 Vlans 10,30,221,250. Dhcp snooping shows fine in 2 vlans :

but problem is with vlan 221, dhcp is not showing and not binding any ip. I saw only something like that :

MAC Address IP Address Lease (sec) Type VLAN Interface
------------------ --------------- ------------ ---------- ---- ----------
64:00:6a:2d:27:1c 172.28.0.174 3112 learned 22 gi45
64:00:6a:2d:8a:3c 172.28.0.140 3143 learned 22 gi38
b8:ac:6f:9b:44:a0 172.28.0.168 3115 learned 22 gi37

a4:ba:db:f8:f6:db 172.28.1.149 30147 learned 250 gi13
64:00:6a:2d:8b:a9 0.0.0.0 108 learned 221 gi2

---

Looks like an output from the snooping database - but its also showing vlan 22 and you dont have snooping on vlan 22.

Make sure you DONT apply snooping on a switch if that switch is running as a dhcp server, also make sure all you trunks switch interconnects being trusted for snooping?

Lastly the snoop D/B wont populate until the client renews its address so have you tired renewing the clients allocation?

[dil_szczecin1]

---

@paul driver wrote:

---

@dil_szczecin1 wrote:

Hello 

I started with dhcp snooping in my network. I got 4 Vlans 10,30,221,250. Dhcp snooping shows fine in 2 vlans :

but problem is with vlan 221, dhcp is not showing and not binding any ip. I saw only something like that :

MAC Address IP Address Lease (sec) Type VLAN Interface
------------------ --------------- ------------ ---------- ---- ----------
64:00:6a:2d:27:1c 172.28.0.174 3112 learned 22 gi45
64:00:6a:2d:8a:3c 172.28.0.140 3143 learned 22 gi38
b8:ac:6f:9b:44:a0 172.28.0.168 3115 learned 22 gi37

a4:ba:db:f8:f6:db 172.28.1.149 30147 learned 250 gi13
64:00:6a:2d:8b:a9 0.0.0.0 108 learned 221 gi2

---

Looks like an output from the snooping database - but its also showing vlan 22 and you dont have snooping on vlan 22.

Make sure you DONT apply snooping on a switch if that switch is running as a dhcp server, also make sure all you trunks switch interconnects being trusted for snooping?

Lastly the snoop D/B wont populate until the client renews its address so have you tired renewing the clients allocation?

---

hello i see now - i din't paste here what i wanted :) - there is no vlan 30 on this switch - vlan 22. So i have 4 vlans 10,22,221,250. 

I don't have a dhcp on the switch and dhcp is not running on this switch, all trunks is trusted even port channel. 

I renewed ip on station and i still got 0.0.0.0 with mac. 

[dil_szczecin1]

i renewed on vlan 221 station :

64:00:6a:2d:72:e6 0.0.0.0 35 learned 221 gi14

:(

counting to zero and out from table 

[paul driver]

Hello

Curious disabling snooping for that vlan, does the client retrieve an ip address and does the dhcp binding/ show correct?

What switch models/ios versions are you using?

sh ip dhcp binding
sh ip dhcp database

[dil_szczecin1]

---

@paul driver wrote:

Hello

Curious disabling snooping for that vlan, does the client retrieve an ip address and does the dhcp binding/ show correct?

What switch models/ios versions are you using?

sh ip dhcp binding
sh ip dhcp database

---

When i disabling snooping for vlan 221 nothing's change - devices from vlan 221 got correct ip and i don't have any devices in snooping database :

Total number of binding: 5

MAC Address IP Address Lease (sec) Type VLAN Interface
------------------ --------------- ------------ ---------- ---- ----------
64:00:6a:2d:25:df 172.28.0.163 1901 learned 22 gi18
64:00:6a:2d:27:1c 172.28.0.174 3285 learned 22 gi45
64:00:6a:2d:8a:37 172.28.0.151 2720 learned 22 gi19
64:00:6a:2d:8a:3c 172.28.0.140 3545 learned 22 gi38
b8:ac:6f:9b:44:a0 172.28.0.168 2396 learned 22 gi37

sh ip dhcp binding (i don't have dhcp server on switch) :

DHCP server disabled.
The number of used (all types) entries is 0
The number of preallocated entries is 0
The number of allocated entries is 0
The number of expired entries is 0
The number of declined entries is 0
The number of static entries is 0
The number of dynamic entries is 0
The number of automatic entries is 0

IP address Hardware address Lease expiration Type State
---------------- ------------------ ------------------ ----------- -------

sh ip dhcp database
% Wrong number of parameters or invalid range, size or characters entered

switch Cisco SG300-52 52-Port Gigabit Managed Switch

sh version
SW version 1.4.9.4 ( date 04-Jun-2018 time 00:07:58 )
Boot version 1.3.5.06 ( date 21-Jul-2013 time 15:12:10 )
HW version V02

[dil_szczecin1 · Accepted solution]

Ok i find solution myself :D

There was native vlan 221 typed on root switch.

I deleted native vlan and everything is ok.