DHCP_SNOOPING drop message

[Mlex1]

Hello every one, i see logs on ISP port, port connected to my switch 

008973: Mar 4 09:24:39.305: %DHCP_SNOOPING-5-DHCP_SNOOPING_UNTRUSTED_PORT: DHCP_SNOOPING drop message on untrusted port, message type: DHCPOFFER, MAC sa: 789a.18ba.23df
008974: Mar 4 09:26:09.528: %DHCP_SNOOPING-5-DHCP_SNOOPING_UNTRUSTED_PORT: DHCP_SNOOPING drop message on untrusted port, message type: DHCPNAK, MAC sa: 5087.89b2.7ed0
008975: Mar 4 09:29:28.110: %DHCP_SNOOPING-5-DHCP_SNOOPING_UNTRUSTED_PORT: DHCP_SNOOPING drop message on untrusted port, message type: DHCPNAK, MAC sa: 707d.b984.8a30
008976: Mar 4 09:31:15.681: %DHCP_SNOOPING-5-DHCP_SNOOPING_UNTRUSTED_PORT: DHCP_SNOOPING drop message on untrusted port, message type: DHCPNAK, MAC sa: 5087.89b2.7ed0
008977: Mar 4 09:34:39.314: %DHCP_SNOOPING-5-DHCP_SNOOPING_UNTRUSTED_PORT: DHCP_SNOOPING drop message on untrusted port, message type: DHCPOFFER, MAC sa: 789a.18ba.23df
008978: Mar 4 09:38:18.986: %DHCP_SNOOPING-5-DHCP_SNOOPING_UNTRUSTED_PORT: DHCP_SNOOPING drop message on untrusted port, message type: DHCPNAK, MAC sa: 5087.89b2.8004
008979: Mar 4 09:41:15.674: %DHCP_SNOOPING-5-DHCP_SNOOPING_UNTRUSTED_PORT: DHCP_SNOOPING drop message on untrusted port, message type: DHCPNAK, MAC sa: 5087.89b2.7ed0

when i checking uplink port i see mac address more then 1700 mac address

i should type ticket to ISP or solve local problem

[M02@rt37 · Accepted solution]

Hello @Mlex1 

ISP is delivering a shared L2 network ? Is it an IXP ?

Open a case to your ISP support.

[Mlex1]

Hello 

ISP is delivering a shared L2 network ? i guess yes 

Is it an IXP ? not 

Open a case to your ISP support. understood 

[David Ruess]

Hello,
>From the output it appears the ISP network is sending DHCP Offer messages on that port to your network. Are clients supposed to be getting their IP addresses from the ISP DHCP server? If so you need to make the port trusted. If not then contact the ISP to see if they have a DHCP server sending your clients Offer messages. You may also check your clients to see if they are requesting the DHCP IP. I dont know a DHCP server will send erroneous DHCP offers unless specifically asked or clients are up for renewal. 
-David 

[Mlex1]

Hello 

Are clients supposed to be getting their IP addresses from the ISP DHCP server? not 

f not then contact the ISP to see if they have a DHCP server sending your clients Offer messages.  already send teckit to isp