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.

Filter by
Sorted by
Tagged with
1
vote
2answers
196 views

Cisco DHCP Router

I have come across an issue and I’m not sure on how to resolve. I’m trying to get the router to assign the PC’s within my network IP addresses. I have excluded the ones which i wish to not be used ...
1
vote
1answer
31 views

How do devices with static IP behave themselves when plugged to a new network? [closed]

I'm trying to understand how to determine if a device plugged to my PC with Ethernet cable has a static IP. What I'm trying to do is to sniff DHCP packets that it sends and by looking at DHCPDISCOVER ...
1
vote
2answers
402 views

What happens when DHCP client and server are on different VLANs [closed]

I'm trying to create a lab on PT and I've attached an image. But for some reason my PC is not able to get an IP address from the DHCP server. There is no issues with layer 1 and layer 2. I checked ...
3
votes
2answers
183 views

Client timeout for Cisco IOS Static DHCP Pool

I'm not a network admin, but I have an old Cisco Catalyst 3560 for my network. I've successfully set up a DHCP Pool: ip dhcp pool 192.168.0.0 network 192.168.0.0 255.255.255.0 default-router 192....
1
vote
1answer
679 views

No DHCPOFFER message captured in Wireshark

I am looking for the answer why packet captures in Wireshark doesn't contain DHCP offer message. I was trying to capture packets directly on the computer with installed Wireshark and doing a SPAN ...
1
vote
0answers
227 views

Cisco ASA: Windows DHCP doesn't bind IP address after failover change active [closed]

Equipment and soft: Two Cisco ASA 5540, ASA ver. 9.1(7)32, active/standby failover DHCP server: Windows server 2016 Anyconnect VPN clients get IP addresses from DHCP servers. Everything works ...
1
vote
0answers
140 views

DHCP over Frame Relay [closed]

I have two co-operate buildings. Building A is connected to building B via frame relay. Building A has the main switch server (with VLAN info) and a DHCP server. I need Building B devices to receive ...
0
votes
1answer
800 views

Is there such a thing as a “fallback” DHCP server? [closed]

Suppose I have a network 10.0.0.0/24, and a DHCP server that allocates addresses under that network. My question is simple — I have a separate box which is also capable of acting as a DHCP server. ...
3
votes
2answers
8k views

Assign IP address using Router and Switch (DHCP)

I currently have a router and I was wondering if I could connect one of the LAN ports to a switch to connect more devices through Ethernet. I need each device to have a local IP address. I know that ...
1
vote
0answers
347 views

Cisco ASA L2TP remote-access VPN with addresses assigned by DHCP

I have an ASA with a working Cisco VPN Client configuration set up. I am trying to phase out the Cisco VPN Client, initially in favour of L2TP. The Cisco Client policy has end-users fetch their ...
1
vote
1answer
84 views

Cisco 887VA not handing out IPs to new requests

A few days ago seemingly with no changes (other than we changed the adsl mode on the controller). DHCP has stopped working for 2 of the 3 vlans we have configured on a Cisco 887VA. From the Cisco ...
2
votes
0answers
66 views

DHCP ivp6 vs DHCP ipv4 router config (cisco) [closed]

When setting up a router as dchp server in ipv4, we specify a pool under which we give the network and the default-gateway and that's it: However in ipv6 stateless dhcp , we create the pool then ...
3
votes
1answer
108 views

ip dhcp class command

Here is a DHCP configuration that we have here: ip dhcp class range ip dhcp pool abc network 10.10.10.0 255.255.255.0 default-router ... class range address range 10.10.10.10 10.10.10.254 My ...
1
vote
2answers
248 views

Get DHCP IP with subinterface

Router0 has 1 subinterface on gi0/0 and can't get a ip trough dhcp. Is there something I forgot? The configs: Router0(got no ip from dhcp): interface GigabitEthernet0/0 ip address dhcp duplex ...
1
vote
1answer
122 views

Dhcp Broadcast Through Switches

Think of a pc connected to switch1. Sw1 is connected to sw2(trunk port on both switches) and sw2 is connected to a router(dhcp server). Pc sends a dhcp broadcast. Does sw1 passes the broadcast through ...
3
votes
1answer
100 views

DHCP Broadcast on SVI

Think of a dhcp broadcast going through multiple switches. What happens to that broadcast when it reaches the vlan interface (svi)?
-3
votes
2answers
80 views

How can TCP be used in order to implement DHCP and under which circumstances is this preferable?

I am pretty new to the computer networking studies and was learning about the DHCP protocol. It is implemented based on UDP, as I've gathered, but is there a way for it to be implemented over TCP? ...
1
vote
1answer
60 views

Why aren't we using digital signatures for the DHCP?

Why aren't we using digital signatures for the DHCP in order to stop Rouge DHCP attacks?
0
votes
1answer
48 views

faild hardware address for ifd ge-0/0/0 failed on junos-vsrx-12.1X47-D20.7-domestic vmware machine

I have been trying to configure dhcp client on ge-0/0/0, I have asked a question before about it in this link At first the solution provided worked, but when I started the virtual machine again it ...
0
votes
2answers
3k views

Importance of DHCP option 12, client host name

The main purpose of a DHCP server is to provide dynamic configuration for a group of hosts (mainly IP, Gateway and DNS). There are several options that can also be sent. Option 12 (client hostname), ...
0
votes
2answers
692 views

Device need Telnet to configure, but no IP is assigned

I have a UPS device connected to a Juniper EX switch. According to the UPS device documentation the device used DHCP and BOOTP to obtain a IP. This is part of a management network which doesn't have a ...
2
votes
1answer
652 views

Add a router with dhcp to existing lan and create a secondary private network [closed]

I'm not a network guru. I have had this scenario a few times at a hackathon or small event for technical people. There are usually a group of 50-200 but with an average of anywhere up to 4 devices per ...
3
votes
1answer
378 views

Configuring DHCP on Juniper junos-vsrx-12.1X47-D20.7-domestic on vmware

I'm preparing for JNCIS-SEC exam. I used junos-vsrx-12.1X47-D20.7-domestic image to create virtual machine in order to practice for the exam. I am following this to configure the vsrx. When I do the ...
4
votes
1answer
19k views

Assign an IP to a MAC Address to DHCP POOL

The idea is that I want to have a static IP for the MAC computer always assign me the IP . please help , as would the commands ? I have a cisco 3650 switch core where I configured the DHCP and VLAN ...
0
votes
1answer
77 views

Connectivity from DHCP-based machines to servers with static IP addresses on the same gateway

I have Comcast service with 5 static IP addresses, using a Cisco DPC3939B as the cable modem. In addition to the 5 machines with static IP addresses, there are additional devices that get their IP ...
1
vote
1answer
145 views

Can a machine be its own DHCP server for another interface?

I was wondering if a single machine (with several network interfaces) can be, at the same time, a DHCP server and a DHCP client, that is the server would dynamically attribute an IP address to an ...
1
vote
1answer
379 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 ...
2
votes
1answer
1k views

DHCP relay on Juniper MX

Hi I got a problem with bootp relay on a juniper router(s). I got helpers bootp interface configured with: irb.10 broadcast server 10.20.1.10 server 10.20.1.11 theres several irb ...
2
votes
3answers
210 views

Sonicwall DHCP client option code

Is it possible to set DHCP option codes for the DHCP client (the WAN interface)? I am quite sure that you can send options in a DHCP request, I quote: "This option is used by DHCP clients to specify ...
4
votes
2answers
919 views

Detect DHCP pool is full from monitored DHCP traffic

Is there any way to detect full DHCP pool just from DHCP traffic?? I assume for simplicity just one DHCP server in network. I have found in RFC 2131, that DHCP NAK is sent only in this case: ...
14
votes
3answers
32k views

How broadcasting works on different networks?

I was reading DHCP ( RFC 2131 ), I have basic knowledge about Relay Agent and Broadcasting. But for Understanding DHCP in depth, I felt like I have to know Broadcasting and Relay Agent ( RFC 1542 ) in ...
3
votes
1answer
2k views

Why are DHCP ACK and REQ messages broadcast in Link Layer?

When I look at the protocol, I see that DHCP Request and Acknowledgement are both broadcast in the link layer. However at that point, both sides actually know each other's MAC addresses. Why do they ...
2
votes
2answers
23k views

How IP helper address works?

How IP helper address works and what is the difference between dhcp and IP helper-address .please explain in brief.
1
vote
1answer
2k views

Two router DHCP server setup

Here is my topology: I'm trying to get a DHCP IP address for a Windows XP client, but when I do the ipconfig /renew command, it said, can not use the rpc server and failed to get an ip address from ...
1
vote
2answers
408 views

VLAN with PAT cannot get past router

I'd like to start off saying that I'm out of my scope here, but I could really use some help. Our ISP gave us the following to connect to our business class internet services. Network: 97.105.48.72 ...
2
votes
2answers
314 views

How to configure Cisco IOS DHCP client to have a backup IP address?

I want to setup an 881 router such that it gets its IP address via DHCP. But I also want to setup a backup IP address in case it failed to obtain an IP via DHCP. I tried setting secondary IP address ...
1
vote
1answer
531 views

Choosing a DHCP pool from which to assign an IP address

I have Router, and there are three DHCP pools: 10.0.1.0/24, 10.0.2.0/24, and 10.0.3.0 /24. Three LANs are connected to this router. If a host on the first LAN sends a DHCP Request, how does the router ...
0
votes
3answers
692 views

Unable to ping 192.168.x.x series

My camera IP is in range of 192.168.x.x and I'm using IP in the range of 10.x.x.x series DHCP. When I assign my PC a static IP 10.x.x.x and additional ip 192.168.x.x I am able to ping my camera ip. ...
5
votes
1answer
6k views

DHCP with Brocade

I have the following config on a brocade icx with the premium license for L3 features: stack unit 1 module 1 icx6450-24p-poe-port-management-module module 2 icx6450-sfp-plus-4port-40g-module ! ...
2
votes
1answer
480 views

Does Router automatically exclude default-router address from DHCP leasing?

I am confused with what happens to the default router adddress when we are configuring DHCP in the router. I have the network with 253 hosts, 192.168.1.0/24, and I have configured DHCP in my network. ...
1
vote
1answer
189 views

Set up 2 VLANs and rate limit Internet bandwith

I generally work with software instead of networking so please bear with me. I have a good understanding of simple network principles like subnetting, DHCP, DNS and the like but have a slightly more ...
2
votes
1answer
656 views

How to set up DHCP in tagged VLAN with Cisco 300 switch

I have been searching for a while but not yet found the correct answer. First, I am pretty green with networking, so I will try to explain as precise as possible. I am tasked with setting up a dhcp ...
3
votes
3answers
577 views

Basic networking and DHCP theory

Background We're organizing an event where we need to connect about 10 PCs into a single LAN network (no internet access). We've got some general experience with "home" and "web" networking but we've ...
3
votes
1answer
538 views

DHCP OFFER not reaching client through several routers and ASA [closed]

So recently we received notification from one of our remote branches that certain PCs were unable to connect to the internet. We determined that DHCP was the cause. The basic L3 path between the ...
1
vote
2answers
8k views

Reserve an IP for client on Cisco DHCP server

So I thought I knew how to set up my DHCP Server on my 3550 switch and reserve IP's for clients. I go into the pool I need to reserve the IP in, but I do not have the address command as an option to ...
7
votes
2answers
42k views

dhcpv6 - stateful VS stateless, what is difference between it?

Can someone explain me, what is difference between DHCPv6 Stateful and Stateless? I was looking on the net and, surprisingly, I found only the remains of information but some general comparison or ...
1
vote
0answers
158 views

Is a dedicated DHCP server required for PXE boot? [closed]

Read a lot of posts on PXE server setup. Most of them mention to setup DHCP server. My question is even though we used a managed switch (e.g. Cisco SG-300), which comes with DHCP functionality, do we ...
1
vote
1answer
330 views

Two ip helper for two different services?

There is a vlan5 currently configured with an ip helper-address to forward the broadcast traffic to our DHCP on a different vlan. Works perfectly and everyone is happy. interface Vlan5 description ...
2
votes
1answer
4k views

Single DHCP server for multiple VLANs (packet tracer)

I have a layer 2 switch, PC 1 connected to port 1 and PC 2 connected to port 2. Port 1 is in VLAN 20 Port 2 is in VLAN 21 Can I use a single DHCP server without a router and give IP to both the PCs?...
1
vote
2answers
77 views

Is it possible to enable DHCP on multiple hosts via Cisco switches or routers? [closed]

I think I know the answer to this, but thought I ought to ask around. When setting up new networks with multiple hosts, like a university computer lab VLAN with 30+ workstations, for instance, is it ...

1 2
3
4 5
9