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

Wed Nov 6 12:59:44 UTC 2013

interface eth1
{
            AdvSendAdvert on;
****       AdvManagedFlag off; ***
****       AdvOtherConfigFlag off; ***
...

Are you sure? Advertising M=0 and O=0 as part of an RA ICMPv6 message and yet you want IPv6 hosts to use DHCPv6?

-- H.

Von: dhcp-users-bounces+harald.albrecht=siemens.com at lists.isc.org [mailto:dhcp-users-bounces+harald.albrecht=siemens.com at lists.isc.org] Im Auftrag von banglang huang
Gesendet: Mittwoch, 6. November 2013 12:29
An: Users of ISC DHCP
Betreff: Re: How to configure the relay agent in One DHCP Server with isc-dhcp-server ipv4?

I have another issue now, it is the IPV6 dhcrelay.

My configuration file on AP(2001:aaaa:bbbb:1234::110)

#dhcpd.conf
authoritative;
default-lease-time 72000;
max-lease-time 144000;

.......

subnet6 2001:aaaa:bbbb:1234::/64 {
  interface eth0;
  range6 2001:aaaa:bbbb:1234:: /64;
 /*option routers is unacceptable argument here*/
}

subnet6 2001:aaaa:bbbb:1235::/64 {
  interface eth0;
  range6 2001:aaaa:bbbb:1235:: /64;
}

subnet6 2001:aaaa:bbbb:1236::/64 {
  interface eth0;
  range6 2001:aaaa:bbbb:1236:: /64;
}

the ifconfig result on DHCP Relay Agent  (static ipaddress)
eth0  2001:aaaa:bbbb:1234::1
eth1  2001:aaaa:bbbb:1235::1
eth2  2001:aaaa:bbbb:1236::1

And I run the dhcrelay daemon like this

dhcrelay -6 -u eth0 -l eth1 -l eth2

furthermore, the daemon radvd is runned on DHCP Relay Agent,
below is the configuration file. /etc/radvd.conf

interface eth0
{
          AdvSendAdvert on;
          AdvManagedFlag off;
          AdvOtherConfigFlag off;

          prefix 2001:aaaa:bbbb:1234::/64
          {
                      AdvOnLink on;
                      AdvAutonomous on;
                      AdvRouterAddr on;
          };
};

interface eth1
{
          AdvSendAdvert on;
          AdvManagedFlag off;
          AdvOtherConfigFlag off;

          prefix 2001:aaaa:bbbb:1235::/64
          {
                      AdvOnLink on;
                      AdvAutonomous on;
                      AdvRouterAddr on;
          };
};

interface eth2
{
          AdvSendAdvert on;
          AdvManagedFlag off;
          AdvOtherConfigFlag off;

          prefix 2001:aaaa:bbbb:1236::/64
          {
                      AdvOnLink on;
                      AdvAutonomous on;
                      AdvRouterAddr on;
          };
};

After finishing by above configuration , the Client can get IPv6 address, but can not ping DHCP Server or the specific ethernet port(the same network)

2013/11/5 banglang huang <banglang.huang at gmail.com<mailto:banglang.huang at gmail.com>>
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<mailto: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: ÄÚÇ¶Í¼Æ¬ 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<mailto: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 ??
>

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