Netgate Store

Author Topic: Reject or Block DHCP request  (Read 131 times)

0 Members and 1 Guest are viewing this topic.

Offline hibrid0

  • Newbie
  • *
  • Posts: 1
  • Karma: +0/-0
    • View Profile
Reject or Block DHCP request
« on: February 01, 2018, 12:16:30 pm »
Hi, I have my network with pfSense and call the ISP to disable the DHCP on his modem, that's OK.
But sometimes the ISP reactive the DHCP on his modem.

I want to know how to block the dhcp traffic from my Lan to the ISP modem.

My Network:

LAN Users-->>ETH1 (192.168.100.0/24)PfSense -->ETH1(192.168.0.101 )-->>ISP Modem









Offline KOM

  • Hero Member
  • *****
  • Posts: 5937
  • Karma: +724/-24
    • View Profile
Re: Reject or Block DHCP request
« Reply #1 on: February 01, 2018, 12:31:48 pm »
How is it causing a problem?  If your WAN is set to static IP, it won't care if upstream can offer addresses, and your LAN won't ever see those offers anyway.

Offline JKnott

  • Hero Member
  • *****
  • Posts: 1464
  • Karma: +65/-17
    • View Profile
Re: Reject or Block DHCP request
« Reply #2 on: February 01, 2018, 03:32:02 pm »
Quote
I want to know how to block the dhcp traffic from my Lan to the ISP modem.

???

If you have pfSense between your LAN and the modem, then what happens WRT DHCP on the WAN side shouldn't appear on the LAN.  Also, consider how DHCP works.  A client REQUESTS and a server provides an address.  Any DHCP request on your LAN will not make it past pfSense.  So, any device using DHCP on your LAN should get an address from pfSense and not the ISP.  The only exception is if you configured pfSense as a DHCP relay.

Bottom line, it's unlikely you're seeing DHCP addresses from your ISP on your LAN.  Why do you think that's happening?

This page unintentionally left blank.