DHCP – IT Blog

Warning: Host-bound traffic for protocol/exception DHCPv4:bad-packets exceeded its allowed bandwidth

Once I noticed the following warnings in the Juniper MX204 logs:

How to configure DHCP client on Huawei Sx300

For example, I will configure a DHCP client on the Huawei S2326TP-EI switch so that it receives an IP address from a DHCP server.

Testing a DHCP server with dhcpperf

dhcpperf is a DHCP load testing tool.

Configuring DHCP Relay on Cisco Nexus 3064

For example, I will configure DHCPv4 Relay on Cisco N3K-C3064PQ-10GX. Initially, I configured this switch for L2, but some VLANs had to be configured as L3 and DHCPv4 Relay enabled.

Blocking DHCP packets on D-Link DES-38xx

Nothing complicated, just create an ACL rule, due to which on certain ports the switch will drop or pass packets that go to client port 67 from a DHCP server and thus it will not receive IP from unnecessary DHCP servers.

Configuring DHCP Snooping on MikroTik

I will give an example of setting up DHCP Snooping on MikroTik (RouterOS) to block third-party DHCP servers:

Suppression of DHCP servers (dhcdrop)

dhcdrop is a utility for suppressing unnecessary DHCP servers and stress testing.

Blocking DHCP servers on FoxGate switches

For example, I’ll take a FoxGate S6224-S4 switch; on other models, the configuration is almost the same.

First, enable the dhcp snooping function:

ip dhcp snooping enable

Continue reading “Blocking DHCP servers on FoxGate switches”

Block third-party DHCP servers on the Huawei Quidway S2300 (DHCP Snooping)

I will give an example of how on the Huawei Quidway S2300 switch (using the S2326TP-EI as an example) to allow receiving DHCP responses from the uplink port and prohibiting client responses.

Configuring DHCP+TFTP for DOCSIS

Recently, it was necessary to configure the issuance of IP addresses to several old DOCSIS modems and the host located after the modem.
At hand was the Arris Cadant C3 and Thomson TCM-420 modems.

First of all, let’s start a DHCP server that will issue IP addresses to modems, for example, as I described in this article – Installing and configuring isc-dhcp-server.
And also we will launch a TFTP server on which there will be files for modems, for example, as I described in the article – Installing and Configuring a TFTP Server