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Questions tagged [dhcp-snooping]

For questions about DHCP Snooping on Network devices. For instance, you want to setup DHCP Snooping on your user access VLAN, but don't know how and need help.

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Juniper and EdgeCore dhcpv6-relay remote-id (option 37)

I have the following problem. I have minimal configuration of dhcpv6-relay agent on QFX5100. Before the QFX, there is an Edgecore switch on which DHCPv6 snooping is enabled. The problem occurs as soon ...
Libor's user avatar
  • 11
0 votes
1 answer
70 views

DHCP Snooping in a DHCP Helper/Relay Environment with a centralized DHCP server

It seems impossible to configure DHCP snooping in an environment with a centralized DHCP server. [ Using the following global configuration on all switches, the DHCP server is attached to access ...
Caine Kiewit's user avatar
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1 answer
48 views

Does this DHCP Server need a trusted ARP Inspection port in IOS?

The switch runs Cisco IOS. You want to configure security on Switch 1. The objective is configuring Dynamic ARP Inspection on Switch 1. Which Ports or port will you configure as Trusted? A) None of ...
Atheesh Thirumalairajan's user avatar
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0 answers
106 views

Configure DHCP snooping with no option 82 on a pure layer 2 Juniper ex2300 using ELS

I have a Juniper ex2300 switch in a mostly-cisco environment (no MIST). On my cisco devices, I have DHCP snooping configured per vlan, with option 82 disabled on the access-layer switches because they ...
Cybersoldier's user avatar
0 votes
1 answer
289 views

Trusted and Untrusted ports in DHCP Snooping / ARP Inspection

From a networking course I am following, I've learned that in D. ARP Inspection, ports connected to routers or to other switches should be configured as trusted while the user ports should remain ...
Mitrixsen's user avatar
  • 803
0 votes
0 answers
19 views

Arp Access-List Without An Interface [duplicate]

I have dhcp snooping an arp inspection setup on my VLAN. I have a number of clients that need to be statically set on this VLAN but still plug into a DHCP access port on the VLAN. I have ip dhcp ...
JukEboX's user avatar
  • 461
0 votes
2 answers
655 views

IP Snooping\ARP Inspection With Static Devices On DHCP VLAN

Consider this network: I have enabled DHCP snooping on my system. Switch A has the DHCP connected and the port on VLAN 70 for DHCP has been trusted to allow for reading the database and passing ...
JukEboX's user avatar
  • 461
0 votes
2 answers
1k views

ip dhcp snooping Kills DHCP Ports

I am working on implementing DHCP Snooping on my switches and have found that when I do so it kills the DHCP connection to the clients. The network is as such: The server with DNS is providing DHCP ...
JukEboX's user avatar
  • 461
3 votes
1 answer
469 views

The equivalent of "ip dhcp snooping information option allow-untrusted" on NX-OS

I'm adding DHCP Snooping to the core switches but I'm unable to find the equivalent of ip dhcp snooping information option allow-untrusted from Cisco IOS in Cisco NX-OS. I've done some tests without ...
Vinícius Ferrão's user avatar
2 votes
2 answers
360 views

Security issues with DHCP snooping on cascading switches

Consider the following topology: This image was copied from here and in this article it specifies the following: Remember that port Fa0/24 on SW2 is an untrusted port from DHCP Snooping’s point of ...
Vinícius Ferrão's user avatar
1 vote
2 answers
1k views

Why do Cisco IOS switches send packets to DHCP servers with zero giaddr field when DHCP snooping is on?

I recently troubleshooted a network where the switch had DHCP snooping turned on and even though the router which was acting as a DHCP server was connected to a trusted port, the client wasn't able to ...
Somenath Sinha's user avatar
2 votes
1 answer
189 views

How to avoid end-user connect their wireless router?

I just replaced our network gears with Aruba 2930f. I had gone through all basic security such as DHCP snooping, DHCP trusted port and BDPU. One thing I don't know if I am able to shut down the sw ...
Will's user avatar
  • 141
1 vote
1 answer
603 views

Dynamic ARP Inspection + IP Source Guard (without DHCP Snooping)

Consider the following scenario I have 2 switches, A and B connected via Po1 (LACP). IP DHCP Snooping turned on for both Switch-A and Switch-B. Dynamic ARP Inspection trust is configured on (Ppo1) on ...
Noob's user avatar
  • 529
1 vote
4 answers
3k views

DHCP snooping problem

I have some problems with a very simple DHCP snooping configuration. I'm using a very simple topology using router on a stick. I use VLAN 10 and VLAN 20. My Clients can get DHCP from my router when ...
Bungicasse's user avatar
1 vote
3 answers
2k views

DHCP Snooping on HP 2510 or alternate

Recently encountered issue of Rogue DHCP, so wanted to protect my network by implementing DHCP snooping. Have HP 2510 Switches installed, but after searching the internet i found that HP 2510 switches ...
Asim Ali's user avatar
1 vote
1 answer
672 views

DHCP snooping not blocking rogue server

Everything I've read on this says this should work, but for some reason it's just not happening. I've got a switch connected to a DHCP server (192.168.10.3) in VLAN 10, and two machines in VLAN 7: a ...
user avatar
4 votes
3 answers
18k views

Dynamic ARP Inspection ports err-disable with %SW_DAI-4-PACKET_RATE_EXCEEDED

Ports in my network on random switches(connected to Windows 7 workstations) are going into err-disable because of dynamic arp inspection. Ports are going into err-disable because there are too many ...
user4608's user avatar
  • 177
4 votes
2 answers
2k views

arp inspection with dhcp snooping

My network Figure is : In this figure switch 3750 is my main switch and all of ACL and vlaning and DHCP server and... comands are in this switch. I want set ARP inspection configs for security in my ...
mrb's user avatar
  • 93
8 votes
1 answer
2k views

DHCP-Snooping on 3com S4210

I'm setting up dhcp snooping with IP source guard and DAI on some 3com S4210 switches. I found problem with recording bindings in snooping database. In some cases I know that there is PC connected to ...
skvedo's user avatar
  • 81
7 votes
1 answer
1k views

Establishing IP DHCP Snooping

Have establsihed a lab to test IP DHCP SNOOPING prior to implemntation. So far everything works as advertised. Given that the Uplink port of a switch must be trusted, why is it not necessary to add ...
rsebastian's user avatar
8 votes
1 answer
1k views

DHCP Snooping Confusion

I'm trying to work out how to enable dhcp snooping and dynamic arp inspection on our guest network and I'm a little confused.... Here's the situation: We have a hub and spoke topology, with a ...
Alicia's user avatar
  • 83