Questions tagged [dhcp]
For questions about DHCP in in relation to network devices. For instance, you are setting up DHCP on a layer 3 switch.
451
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DHCP Client Traffic not going through IRB interface as expected
I have several Juniper EX4300 series switches that I'm trying to configure to meet the following specifications:
I'd like each switch to manage a /24 DHCP pool that corresponds to a rack
I'd like ...
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DHCP - General relativity
The following image shows a visualization of the DHCP server in action. DHCP servers send a DHCPNACK message in a scenario where the same ip address is trying to be assigned to 2 devices. Is this ...
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DHCP request for multiple IPs at once [closed]
In DHCP, a DHCP client and a DHCP server go through the protocol exchange (DISCOVER, OFFER, REQUEST, ACK) so that the client ends up with an IP address allocated to it that is also tracked in the ...
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Dhp L2TP reservation on cisco 1921
I use a Cisco 1921 as L2TP server.
(I don't want to use RADIUS authentication.)
Please is someone can tell me how is it possible to do IP reservation, using client identification?
I have tried dhcp ...
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138
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CISCO 9800-L Controller internal dhcp not working - GUEST WIFI
I have been trying to configure a guest network for my Cisco Catalyst 9800-L Wireless Controller for some days now. For the guest network, i want it to use an internal dhcp on the controller. I have ...
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bandwidth on WAN link
I would like to understand how a router is able to divide bandwidth among users who are using the same WAN link.
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No access to internet via DHCP, but works with manual IPs
My DHCP server was giving out IPs in the range 10.0.0.1/24, but I ran out of usable IPs, so I changed the subnet to 10.0.1/21 to have more available addresses, however I am now having a weird problem:
...
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IPSec over L2GRE scenario
I wanted to know if this is a valid scenario and if it is possible to implement.
There is a remote site A. and a Data center site B. Both A and B have a edge router which runs an IPSec tunnel. An ...
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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 ...
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198
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HSRP and DHCP problem
I have 2 layer 3 switches DS1 and DS2. There are the same VLANs but different IP addresses on VLAN interfaces.
On DS1:
VLAN 10: 192.168.10.1/24
VLAN 20: 192.168.20.1/24
On DS2:
VLAN 10: 192.168.10.2/...
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Do Directly Connected Routers Need Routing Protocols For DHCP Relay To Work?
Let us say that we have R01, R02, and R03 connected to each other, and each of them is connected to a different subnet SUB01, SUB02, and SUB03, respectively. R03 is set up as a DHCP server, and DHCP ...
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can a layer 2 switch block dhcp from 1 port, both in and out?
Here's what I want to do: "Wall" is the dhcp server from the ISP. "R" is my internal router. "L2" is a hypothetical switch. "fs" is my dhcp server. I want ...
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CISCO cellular Router cannot reach network via my PC
I configured the cellular and my router is connected to the internet ping (5/5) Success
but I still cannot access the internet via PC
Here is my running-conf
Current configuration : 2271 bytes
!
! ...
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What does 'CPE' stand for, and what is it?
In reading up on NextDNS, I came across the add-cpe-id option to dnsmasq:
--add-cpe-id=
Add an arbitrary identifying string to DNS queries which are forwarded upstream.
NextDNS uses this for your '...
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Which device gets the helper-address?
Brand new to networking and trying different scenarios.
PC2 can successfully send packets to PC1 and the DHCP server if a static address is assigned. However, PC2 will not obtain a DHCP address from ...
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Cisco Switch vIOS-L2 in GNS3 and CCNA 200-301
I am reading a preparation book for the CCNA Test 200-301. Currently, I am reading a section about DHCP and VLAN interfaces in a switch. The book shows an example of configuring this.
switch# ...
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Purpose of netmask in dynmic DHCP statement [duplicate]
What is the purpose of the netmask in a dynamic DHCP statement:
ip nat pool poolname 209.165.200.226 209.165.200.240 netmask 255.255.255.224
I know, that I should choose the netmask to be larger ...
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Inconsistent behavior of show ip dhcp pool poolname
show ip dhcp pool Mitarbeiter10 gives the following output:
R1#show ip dhcp pool Mitarbeiter10
Pool Mitarbeiter10 :
Utilization mark (high/low) : 100 / 0
Subnet size (first/next) : 0 / 0
...
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How do I configure a Cisco router to relay DHCP packets to DHCP server on the basis of different VLAN?
Running-Config of RO1
!
interface GigabitEthernet0/0
ip address 192.168.25.26 255.255.255.0
duplex auto
speed auto
!
interface GigabitEthernet0/1
no ip address
duplex auto
speed auto
!
interface ...
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UniFi6 LR access points go into scan loop [closed]
I have a Ubiquiti setup with four Unifi 6LR access points. I manage to adopt them in the controller just fine and I do briefly see the wifi come up, but then it immediately drops. SSH'ing into the ...
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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 ...
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Why my PCs can't get dynamic IPs from DHCP Server?
In Cisco Packet Tracer I created following network
Following is how I configured the DHCP Server
But the computers can't get IP addresses - getting "DHCP failed" message. Why? Please ...
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How to correctly setup a DHCP server in the following network?
So, I've got the following Network Configuration:
Assume that, on the graph, "PCs" can be any device that needs an IP(apart from a router).
Now, as explained on my title, I want to run a ...
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3
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176
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Lost the Static IP/network settings of a device
We have a physical device (lab instrument) that we can only connect to via ethernet. Unfortunately a static IP was set with network settings and these settings has been lost.
We connected our computer ...
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DHCP RELAY AGENT NOT WORKING TO USER(apipa failed)
can someone help me to solved my router 1 as relay agent dhcp.Currently user 5 that connect from switch 1 is not being able to get dhcp ip address.
My router 2 as dhcp server pool and user 3 ,4 is ...
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Can a router provide DHCP to multiple subnets that are connected via switches?
I'm trying to understand if it is possible to have a router (as shown in the below diagram) provide DHCP leases to more than one subnet if the subnets are not directly attached.
If both the printers ...
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Is DHCP in the application layer or the network layer?
Tanenbaum's Computer Networks says:
5.6 THE NETWORK LAYER IN THE INTERNET
...
5.6.4 Internet Control Protocols
In addition to IP, which is used for data transfer, the Internet has
several companion ...
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DHCP Discover Broadcast and its IP (255.255.255) [duplicate]
Cheers, I am trying to learn more about DHCP, and when studying about the session that DHCP goes through every one mentions that it broadcasts a discover message at IP: (255.255.255.255) (as seen here ...
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How to configure a router as a dhcp server for vlans through a Layer 3 switch?
I would like to know what commands to type in the different switches and the router to to make the router function as a dhcp server for each PC in seperate vlans .
I know to create the dhcp pools in ...
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What could be the bottleneck of my load-testing case?
I need to bring up a bunch of my devices in the network to hit some other service, for testing purposes. And I have used GNS3 to simulate that.
As you may find in my GNS3 project, I have such ...
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Question about subinterface DHCP relay CISCO
I want to make 4 PC got DHCP IP address
No problem with left side, but right side 2 PC can't get IP automaitic. I think the problem is DHCP Relay.
How can I use ip helper-address for subinterface of ...
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339
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Is there an equivalent of the Cisco/ Cisco esque command "ip helper-address a.b.c.d" on Mellanox switches?
Apologies for my newbie question. I have recently had a Mellanox switch added to the mix. I was using an "IP helper-address" to forward DHCP requests in different VLANs to my DHCP server(s) ...
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How does DHCP work?
I'm carrying out an experiment to test the mechanism behind DHCP.
In this topology, I disable the link between the switch and the router. However, the computer still request IP address successfully.
...
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1
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How does a DHCP server know which network interface and subnet the new IP address should be on
I've read that DHCP servers add a column to your iptable in your router. A new dynamically created IP address with a network interface and a subnet mask. Then the IP address is matched with your MAC ...
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How can u assign IP addressing for point to multipoint switches that connect to only one router?
I was wondering if I can assign two network address in a LAN while the switches are point to multipoint which connect to only one router.
How will me DHCP going?
Router - Switch 1 - Switch 2,3,4
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how to configure dnsmasq client-identifier for juniper prefix host-name
I have a Juniper switch that has a dhcp-client configured like this:
show interfaces irb unit 0 family inet dhcp
client-identifier {
prefix {
host-name;
}
}
I ...
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Apply Interface Default Gateway to Entire Device
I feel there may be a very simple term for what I trying to do, but I'm not sure what it is, and it is difficult to search for it in concise words.
The shortest description I can come up with: "I ...
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Configuration of DHCP for multiple vlans
I have the following network on Packet Tracer. The hosts are in different vlans each one. My goal is that the DHCP server can give IP to the hosts.
Here is what I made for each vlan (the example is ...
user80646
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Do IPv6 addresses have better persistence with DHCPv6?
I have a LAN with about 25 devices that occasionally grab each other's IP address via DHCPv4. I know there are certain lease time limits and it can be set to very long periods to work it around to an ...
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IRDP protocol nowadays
I'm considering to remove rdisc tool from iputils project (see https://github.com/iputils/iputils/issues/363). This tool implements ICMP Internet Router Discovery Protocol (IRDP).
Is IRDP really ...
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Configure dhcp relay agent and router on stick
I need help. I don't know what i did wrong because i have configured the dhcp pool, subinterfaces and dhcp relay agent. Gateway pc uses static ip address while Branch pc acquired their ip address ...
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Assigning static IPs to VoIP phones in packet tracer
Is there a way to assign IPs and dn to VoIP phones in a network configuration without using DHCP?
Such that if I have PCs and VoIP phones connected to the same switch, which is connected to a router ...
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How to add two VLANs for DHCP Pool
Currently one of my customer has DHCP pool created in Cisco Switch and ip address range is 192.168.25.0/24 (This is a VLAN). Now they have 230 devices and They are going to increase device count by ...
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Assigning static IP address from the DHCP pool range on Cisco 800 series
What happens if I assign a static IP address to a device in a LAN where there is an active DHCP server and the address falls within the configured DHCP pool and DHCP server is Cisco 800 Series?
Most ...
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Cisco DHCP using dynamic updates
I would like to use a configuration on a Cisco router that allows for clients to resolve the names of other clients without the use of mDNS. I have following configuration:
roTST01#show running-config ...
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Cisco IOS - Delay DHCP offers
I have two routers in the same subnet that have a HSRP configuration in order to take over, if one of the device fails. There is the same DHCP configuration on both devices:
ip dhcp pool LAN
network ...
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Communication between subnets on Sonicwall firewall
I have a Sonicwall TZ-350. X0 is the default LAN with IP 192.168.10.1, and X1 is the WAN. I've set up a second local subnet on X2 with IP 192.168.20.1 for a single NAS device (no switch; the device is ...
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DHCP Packet Drops on Return
The DHCP packet makes it from the Security computer all the way to the DHCP server and back to Router1 but gets stuck there. All all packets make it across when the device has a static ip assigned.
...
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Does an IPv4 DHCP Relay Agent care about Option 80 (rapid-commit)
I'm trying to figure out if an IPv4 DHCP Relay Agent needs to care about a rapid-commit (Option 80) included in a DHCP Discover.
My understanding is that the Relay Agent is supposed to simply converts ...
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How does a device receive default gateway IP address?
When and how does a device get information about default gateway in LAN? I know you can define default gateway statically, but which protocol is used when it is not statically defined? Is it from ...
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