How to configure the relay agent in One DHCP Server with isc-dhcp-server ipv4?

[banglang huang]

Thank you very much, I make it now, the two PC clients can get their ip
address on the specific network, 192.168.2.x and 192.168.3.x.


2013/11/5 Glenn Satchell <glenn.satchell at uniq.com.au>

> In subnet 192.168.2.0 you need to define
>
>   option routers 192.168.2.1;
>
> and in subnet 192.168.3.0 you need to define:
>
>   option routers 192.168.3.1;
>
> so that the clients get a default route back to the dhcp server.
>
> Next things to try after that are:
>
> Is there a firewall on the dhcp relay box? It needs to allow udp port 67
> and udp port 68 traffic for all IPs including 255.255.255.255.
>
> Is ip_forwarding enabled on the dhcp relay box? Usually /etc/sysctl.conf
> or a subdirectory to set this.
>
> Is there any useful information in the syslog files? Exactly which file
> will depend on how syslog is configured on your system, but something like
> /var/log/messages or /var/log/syslog.
>
> Next step after that is to sniff packets on the dhcp relay box:
>
>   tcpdump udp port 67 or udp port 68
>
> and see which parts of the handshake you are seeing. My bet is adding the
> routers statement will fix it though.
>
> regards,
> -glenn
>
> On Tue, November 5, 2013 12:59 pm, banglang huang wrote:
> > This picture shows the network topology, A Router( only One eth port)
> with
> > isc-dhcp-server, a PC with 4 ethernet ports and two clients,
> >
> > [image: ÄÚǶͼƬ 1]
> >
> > my configuration file on AP(192.168.1.1)
> >
> > #dhcpd.conf
> > authoritative;
> >
> > subnet 192.168.1.0 netmask 255.255.255.0 {
> >   interface eth0;
> >   range 192.168.1.10 192.168.1.50
> >   default-lease-time 72000;
> >   max-lease-time 144000;
> > }
> >
> > subnet 192.168.2.0 netmask 255.255.255.0 {
> >   interface eth0;
> >   range 192.168.2.10 192.168.2.50
> >   default-lease-time 72000;
> >   max-lease-time 144000;
> > }
> >
> > subnet 192.168.3.0 netmask 255.255.255.0 {
> >   interface eth0;
> >   range 192.168.3.10 192.168.3.50
> >   default-lease-time 72000;
> >   max-lease-time 144000;
> > }
> >
> >
> > the ifconfig result on DHCP Relay Agent
> > eth0 192.168.1.125
> > eth1 192.168.2.1
> > eth2  192.168.3.1
> >
> > And I run the dhcrelay daemon like this
> >
> >   dhcrelay 192.168.1.1
> >
> >
> > But the above configuration can not work, the two PC clients can not get
> > IP, so I really need help.
> >
> >
> >
> > 2013/11/4 Glenn Satchell <glenn.satchell at uniq.com.au>
> >
> >> There is no configuration file for dhcrelay as the options are very
> >> simple. Typical usage is
> >>
> >>   dhcrelay serverip1 serverip2
> >>
> >> where serveip1 is the fully qualified hostname or ip address of the dhcp
> >> server. You can specify multiple servers if you have more than one (eg
> >> failover configuration).
> >>
> >> Full details are in the man page for dhcrelay.
> >> regards,
> >> -glenn
> >>
> >> On Mon, November 4, 2013 3:38 pm, banglang huang wrote:
> >> > Hi all,
> >> >         As I am new to isc-dhcp-server, so I do not know how to
> >> configure
> >> > the relay agent.
> >> >         Is there anyone can tell or show a sample configuration
> >> > file(dhcpd.conf or other) to me ??
> >
>
> _______________________________________________
> dhcp-users mailing list
> dhcp-users at lists.isc.org
> https://lists.isc.org/mailman/listinfo/dhcp-users
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.isc.org/pipermail/dhcp-users/attachments/20131105/eefd50c3/attachment.html>