Ubuntu Networking :: DHCP Server No Longer Responds To DHCP Requests - Can't Ping Gateway
Jul 1, 2010
Back in April I set up a Ubuntu DHCP server and a multiple VLAN network [URL] to migrate our various servers, workstations, etc off the 192.168.1.1 /24 network that everything was on because we where running out of address space. I built out the new network and everything worked great except our AD server would never get an IP address from the DHCP server (static reservation) and even if I set the IP statically on the AD server it couldn't ping the gateway and noone could log in. After several attempts to resolve this, including bringing in outside help, we where never able to figure out what the problem was.
Now 6 months later I have time to revisit the issue without effecting the live network. I used Acronis and imaged the AD server last Friday, cloned it on to another box with the same hardware, and put it up on the new network that's been sitting unused for the last 6 months. Today when I statically set the IP on the AD server (which is what I want) it connects and I can ping it's gateway 192.168.1.1 and all the way across vlans to a test sales agent workstation at 192.168.8.xxx on vlan 800 but only if I statically assign the agents station an IP address.
When I try to get an IP address via DHCP it fails as destination unreachable. Nothing has changed in the last 6 months on the DHCP server but now it for some reason can't ping its default gateway 192.168.1.1. All of the config files are the same as they where left from the post linked above aside from the vlan id's used where changed from 1's to 100's (i.e. vlan 3 is now vlan 300) /etc/network/interfaces
Code:
auto lo
iface lo inet loopback
auto vlan100
[code]....
why it can't reach the gateway, when I do a tcpdump I can see the DHCP requests come in on eth0 but the server never responds and I'm pretty sure its because it isn't "seeing" them since it thinks there isn't a network connection but I don't know how to trouble shoot to find out where the problem lies.
Back in April I set up a Ubuntu DHCP server and a multiple VLAN network [URL] to migrate our various servers, workstations, etc off the 192.168.1.1 /24 network that everything was on because we where running out of address space. I built out the new network and everything worked great except our AD server would never get an IP address from the DHCP server (static reservation) and even if I set the IP statically on the AD server it couldn't ping the gateway and noone could log in. After several attempts to resolve this, including bringing in outside help, we where never able to figure out what the problem was.
Now 6 months later I have time to revisit the issue without effecting the live network. I used Acronis and imaged the AD server last Friday, cloned it on to another box with the same hardware, and put it up on the new network that's been sitting unused for the last 6 months. Today when I statically set the IP on the AD server (which is what I want) it connects and I can ping it's gateway 192.168.1.1 and all the way across vlans to a test sales agent workstation at 192.168.8.xxx on vlan 800 but only if I statically assign the agents station an IP address. When I try to get an IP address via DHCP it fails as destination unreachable. Nothing has changed in the last 6 months on the DHCP server but now it for some reason can't ping its default gateway 192.168.1.1. All of the config files are the same as they where left from the post linked above aside from the vlan id's used where changed from 1's to 100's (i.e. vlan 3 is now vlan 300) /etc/network/interfaces
Code:
auto lo iface lo inet loopback auto vlan100 iface vlan100 inet static
[code]....
why it can't reach the gateway, when I do a tcpdump I can see the DHCP requests come in on eth0 but the server never responds and I'm pretty sure its because it isn't "seeing" them since it thinks there isn't a network connection but I don't know how to trouble shoot to find out where the problem lies.
I have installed dhcp-server on ubuntu. And server is providing ip address to clients (Window machines) but not default-gateway but I have another network in my network and same configuration and same dhcp-server provides every information.
I need to place an Ubuntu machine on a network where I have a DHCP server which does not configure the Degault Gateway parameter (we don't want ordinary users to browse the internet). Is it possible to leave the machine using DHCP and define the Default Gateway manually (as in Windows XP i.e.)? How?
I have installed Centos 5 on a virtual machine (esx4i). I set it to obtain an IP address from the DHCP sever, which is a broadband router, it has been given an IP address of 10.10.11.159 the router is 10.10.11.1 but I can't ping the router and I can't get any access to the network! I have a SCO Openserver server on the same physical box and it works fine so I know the network card & cable is ok.
Fresh install of 10.04.1 server; installs seamlessly; finds network no problem.
However, establishing static connection is driving me batty. Will not take. I've reconfigured "interfaces" file several times. My fingers are numb ifdown-ing and ifup-ing and /etc/init.d/network restart-ing.
I have two files in /etc/network ... interfaces and interfaces~ (one static and the other dhcp). I can switch them in and out of play. The dhcp works and pings out like a champ. static is dead, just dead. Cannot ping router ... nothing.
Currently I have my eth0 interface getting a DHCP address but at times the DHCP server will not be reachable. Sooo what I would like my server to do is if it cannot find a DHCP server assign a static address to eth0. Then start the DHCP service so it can then dish out some addresses.How can I do this? Surely it is possible
I am puzzled with trying to configure a linux (openSUSE) client to dhcp to eBox DHCP server. I am using dhclient to lease an IP address with dhclient eth0 -s 10.45.48.108 and get a response
openSUSE11232CL1 dhclient: DHCPDISCOVER on eth0 to 10.45.48.108 port 67 interval 4 openSUSE11232CL1 dhclient: DHCPOFFER from 10.45.48.108 openSUSE11232CL1 dhclient: DHCPREQUEST on eth0 to 10.45.48.108 port 67 openSUSE11232CL1 dhclient: send_packet: Network is unreachable openSUSE11232CL1 dhclient: send_packet: please consult README file regarding broadcast address.
The server reports eBox141 dhcpd: DHCPDISCOVER from 00:0c:29:3e:57:a3 (openSUSE11232CL1.domain.net) via eth0 eBox141 dhcpd: DHCPOFFER on 10.45.200.2 to 00:0c:29:3e:57:a3 (openSUSE11232CL1.domain.net) via eth0
I interpret this as the server receives the request and the client accepting it but the lease does not last long and the connection breaks. what this could be and why the connection breaks? Or my undestanding is totally wrong on how it works and should work? And BTW, where is that README file that's referenced in the message I receive on the client?
What I need is some information to be studied and learned by me in order to be able to create with Ubuntu Server an Internet Gateway Server. From my ISP I get about 50 public routable IPs through DHCP. Into my LAN I need to forward this public routable IPs to machines but I want to be able to manage bandwidth and also to be able to enable or disable Internet access for every client machine. Maybe with subnets? Maybe with dchp really? It would be nice if it would possible through DHCP!
I'm looking for a method to assign a default gateway via dhcp randomly depending on ether the last char of the mac being odd or even, or the time the user connects. Is there a good reliable way to achieve this?
I have an embedded device for which I've created an html configuration page. This page allows you to set static IPs, dhcp, and can scan for wireless devices.My problem is that in order to access the device it requires that it runs as a dhcp server otherwise people are not assigned an IP and so can not access the embedded devices static IP. (This config page is for the laymen and so they are not the type who are able to set up their own static IPs). One of the potential options is to have the device connect to the network on eth0 acting as a dhcp client. However this prevents me from running a dhcp server.One solution I can think of is running a dhcp server only if it doesn't detect another dhcp server running on the network.
I have a simple system at home where a DSL router is used as a basic dhcp server with one port forward for ssh to a server. I need to allow my daughters, ages 14,12 and 10, to access the net and also email but I want to have complete control and logging. What I'm looking to do is set up the Ubuntu file server I already have on the network to act as a gateway and also add content management and logging as step one.
I also want to add an email server so that all the email comes into the Ubuntu server and then is allowed to be accessed by outlook on their machines after spam/content scanning for valid emails as step two. My question is what, if any, additional software do I need and what options do I have. I've played with dhcp servers at work but never got much beyond ip assignment and network booting so I'm unfamiliar with what is needed for content management and such. As to the email server I've never even played with this at all so I'm completely in the dark as to what I should be looking at to start with. I'm looking for directions, RTFM is fine but right now I'm not sure even WHAT manual/manuals I should be reading.
I am having some difficulties comprehending some networking concepts relating to multiple subnets and dhcp servers, or dhcp relay servers. I have built home networks many times before, and they have all followed a very simple formula. A single subnet, let's say 192.168.1.0 which is fairly typical for me. My network's DNS server is always also my networks DHCP server. Typically at 192.168.1.1. When a DHCP client broadcasts for an IP over the subnet, 192.168.1.1(My DNS/DHCP server) will not only tell the client what it's new IP is to be, but will also tell the client what it's Gateway server is. This is ALSO 192.168.1.1 for me typically.
In this manner, a client broadcasts for networking information and is given a usable IP, and told to use 192.168.1.1 for most other functionality. Very simple. However, I am uncertain how to expand this to other subnets. Say.. 192.168.2.0.
A: I can use a separate DHCP server for each subnet. or B: I can use a DHCP Relay agent for 192.168.2.0 to pass the DHCP requests to the primary DHCP server on the 192.168.1.0 subnet.
Option A: is fairly straight forward and have had it functioning fine, but it is really B: I want to know more about. It seems somehow much cleaner to me. I prefer to centralize as much of my network provisioning services as possible. It makes it easier to manage TYPICALLY. My question though is related to Gateways and the use of DHCP Relay Agents....
I have a Lan with 100 computers with microsoft windows xp and vista on it, and I need to build a CentOS Primary domain control- PDC. So I am building a PDC , with samba 3.x +Ldap ( Light Directory Acess Protocol), with static eth0 and DHCP-server( Dynamic Host Control Protocol) on eth1. Eth0 : 192.168.1.3 Eth1 : 192.168.1.5
Here is the configurations files: == BEGIN uname -rmi == 2.6.18-194.17.4.el5 x86_64 x86_64 == END uname -rmi ==
== BEGIN rpm -q centos-release == centos-release-5-5.el5.centos == END rpm -q centos-release ==
== BEGIN cat /etc/redhat-release == CentOS release 5.5 (Final) == END cat /etc/redhat-release ==
== BEGIN getenforce == Permissive == END getenforce ==
== BEGIN rpm -q yum rpm python == yum-3.2.22-26.el5.centos rpm-4.4.2.3-20.el5_5.1 python-2.4.3-27.el5 == END rpm -q yum rpm python == == BEGIN ifconfig -a == .....
I've only been using linux for a few days so I don't know all the tricks. I'm pretty savy configuring windows networks however.My adapter is (according to windows) a: CNet PRO200WL PCI fast ethernet adapterLinux says it is a: 21x4x DEC-tulip compatible 10/100 EthernetI do seem to be getting an ip address from the DHCP router, but I cannout ping any other ips or connect to the internet.I've tried a bunch of different options, switching things back and forth, but it still doesn't work, and honestly i don't even know what some of the options mean.
ALSO, if this helps: paladin:~ # ifconfig eth0 Eth0 Link encap:Ethernet HWaddr 00:08:A1:03:3C:99
I have multiple public ip addresses.My DSL modem blocks ping from a server behind the modem (nb6+4w) modem lan ip (gateway) is xxx.xxx.xxx.105the server is xxx.xxx.xxx.107If I DMZ this server it responds to pings.If i don't want to use DMZ, what service is ping using.I have set up virtual server 443 to this 107 ip as it's a SSL server
i want to disable all DHCP request, can i turn off the client that if a MAC address changes a dhcp request is not automatically made?reason for this: I have HP blade running with an Intel NC260M mezzanine card running with virtual connect. I have experienced problems with firmware levels with this card where the virtual connect mac address is ignored and the real MAC displayed. As we are using bonds on the servers and have 6 NICs installed we have to tie down the MAC address to a bond. A blade was replaced today without the firmware update and the real MAC appeared, a dhcp request was made and my-eth[2-3] and resolv.conf files were over-written by the dhcp supplied
So, I have an Virtual Machine running CentOS 5.4. It sits behind a hardware firewall which also does NAT'ing. I've set up plenty of these, so I know for sure the firewall and NAT rules are set up correctly. From the host, I can ping anything in my subnet and the gateway. But I can't ping anything else beyond the gateway. I can perform DNS queries and when I try to ping, it finds the appropriate IP address.But from the outside, I can ping the PUBLIC address (It's a 1 public to 1 private address NAT, not 1 public to multiple private). I've tried it with IPTABLES on and off, with no change.
5.10 Breezy configured as machine controller. Works great eth0 is a fixed IP to communicate with controller comms board. Not easy at all to alter - the comms board is hard coded to listen on eth0 for commands.
I can use eth1 as the default gateway and ping google.com, etc. But when I now attempt to communicate with the controller with netcat, e.g.
Code: echo !HH | nc 192.168.1.6 80
I obviously never get an answer since the request is passed via eth1. Using the -g option with netcat doesn't work either. I had a look at iptables but it doesn't seem to be able to do what I want. How I can still use eth0 as my communication port to the controller whilst eth1 is the default gateway?
This dhcp server is configured with redhat enterprise edition. I found that logs are generating in the following path /var/log my doubt is how can i setup the logs generating for a specified day.
I have a strange problem for internet. My clients (winxp - S2) can't get internet.Let me explain my scenerios. Fedora 10 with lan (eth0) having direct internet from dsl model, client (XP service pack 2) can use samba shares using dhcp (wlan0) installed in Fedora 10 box. client can ping my linux box.Now problem is: client (dosbox) can ping the google ip address (i.e ping 74.125.39.106) but can't use 'ping www.google.com'. That means ping with ip works for internet from my client. My linux box can. I can use internet from FC10 but can't use iexplorer from my client to have internet. I have enable ipmasquarding in Firewall and dhcpd is running on wlan0 for dynamic ip address of my clients.Can someone suggest me what kind of problem having I? What should i do to success iexplorer for internet? what possibly am i missing?
Does anyone know if you switch networks Where you have your servers hosted on a Non-DHCP Network, and you switch your IP addresses, then do you have to switch change/assign your new gateway address? I'm not sure if its manually assigned? How do you do it? Also what about nameserver resolving?
first: PXE flawless bind to dhcp address but put next binding state to free second: when installer calls init script to reinit ethernet driver (e1000 (vmware)) binding fails 11.2 opensuse fail to reinit dhcp with log entry "no free leases" third: when manual set network install works how to preserve dhcp lease on reinit of driver?
I have an embedded device for which I've created an html configuration page. This page allows you to set static IPs, dhcp, and can scan for wireless devices. My problem is that in order to access the device it requires that it runs as a dhcp server otherwise people are not assigned an IP and so can not access the embedded devices static IP. (This config page is for the laymen and so they are not the type who are able to set up their own static IPs). One of the potential options is to have the device connect to the network on eth0 acting as a dhcp client. However this prevents me from running a dhcp server. One solution I can think of is running a dhcp server only if it doesn't detect another dhcp server running on the network. However I have no idea how this could be setup.
Operating system: Debian Lenny 5.08 (2.6.26-2-amd64 #1 SMP Tue Jan 25 05:59:43 UTC 2011 x86_64 GNU/Linux).
I have a network iface eth0 with 2 virtual IP addresses (117.20.2.111 117.20.2.112). The virtual IP addresses I have setup by simply running:
Code: ifconfig eth0:1 117.20.2.111 up
This has worked fine for 2 virtual IP's but the third one (117.20.2.133) will not respond to ping's though it does respond to arpping's. There are no firewall iptable rules:
Output of route -n: Code: Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 117.20.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 117.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 eth0 0.0.0.0 117.20.2.1 0.0.0.0 UG 0 0 0 eth0
Output of ip rou ls: Code: 117.20.2.0/24 dev eth0 proto kernel scope link src 117.20.2.110 117.0.0.0/8 dev eth0 proto kernel scope link src 117.20.2.111 default via 117.20.2.1 dev eth0
The dhcp doesnt work unless i put a switch or router between the ubuntu gateway and the connecting computer.
setup
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Im on ubuntu 10.04. is this normal? or should i be able to connect without having a router or switch between the ubuntu server and the internal network....
I posted it on another forum, but could not get response,So I have this cenOS, Ubuntu and windows operating system running on virtual machines.Now I gave them manual ip address, both ubuntu and windows machines can ping the default gateway, but not the CentOS.It should forward 0.0.0.0. to my cisco router address(192.168.5.254),
I have 2 Ethernet connections, one (eth0) for the internet which gets set with dhcp, and one (eth1) for my internal network on which I have dhcp3-server running. I set eth1 to use static IP in interfaces, but every time I reset the network, it is fine for a couple of minutes, and switches over do being served by my own dhcp server on the same machine. (the interfaces file clearly says "iface eth1 inet static")
I reinstalled Ubuntu server, now, as always I have to start off with 8.04 then upgrade to 10.04, and I've never had a problem with this before on this machine or any other for that matter. The problem is, this time I have installed and Ubuntu installer cannot see a DHCP, I go a head and install anyway and fire up Ubuntu and there is no internet access, I have two network cards plugged in, when I type in ifconfig it shows only lo and no network cards, and yet when I check lspci ot shows both network cards are there and when either are plugger in it shows connection on both the connector at the stack end and on the router.
