Description

This article provides information on how a Win 7 client obtains the IPv6 default gateway from a SRX device, which is running as the DHCPv6 server.

Symptoms

  • A SRX210 device works as a DHCPv6 server.
  • A Win 7 PC connects to its fe-0/0/3 .
  • Win 7 needs to obtain the IPv6 address and default gateway from SRX.

Solution


The IPv6 client needs to obtain the default gateway via the server with RA enabled. For example:
system {
    services {
        dhcp-local-server {
            dhcpv6 {
                overrides {
                    interface-client-limit 100;
                }
                group my-group {
                    interface fe-0/0/3.0;
                }
            }
        }
    }
}
interfaces {
    fe-0/0/3 {
        unit 0 {
            family inet {
                address 192.168.3.1/24;
            }
            family inet6 {
                address 2001:0200::1/64;
            }
        }
    }
}
protocols {
    router-advertisement {
        interface fe-0/0/3.0 {
            managed-configuration;
            other-stateful-configuration;
            default-lifetime 3600;
            prefix 2001:200::/64 {
                no-autonomous;
            }
            prefix ::/0 {
                no-autonomous;
            }
        }
    }
}
access {
    address-assignment {
        pool 1 {
            family inet6 {
                prefix 2001:200::/64;
                range 1 {
                    low 2001:200::10/128;
                    high 2001:200::20/128;
                }
                dhcp-attributes {
                    dns-server {
                        2001::253;
                    }
                }
            }
        }
    }
}
Win 7 client output:
C:\Users\hawkwang>ipconfig/all
Ethernet adapter Local Area Connection:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Intel(R) 82567LM Gigabit Network Connection
   Physical Address. . . . . . . . . : 00-22-68-17-DC-D8
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   IPv6 Address. . . . . . . . . . . : 2001:200::10(Preferred)
   Lease Obtained. . . . . . . . . . : 2012?6?28? 16:18:09
   Lease Expires . . . . . . . . . . : 2012?6?29? 16:18:08
   Link-local IPv6 Address . . . . . : fe80::390d:c2b5:2db4:45c8%17(Preferred)
   Autoconfiguration IPv4 Address. . : 169.254.69.200(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.0.0
   Default Gateway . . . . . . . . . : fe80::224:dcff:fe16:7403%17
   DHCPv6 IAID . . . . . . . . . . . : 184558184
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-16-9F-F1-9B-00-22-68-20-09-22

   DNS Servers . . . . . . . . . . . : 2001::253
   NetBIOS over Tcpip. . . . . . . . : Enabled


C:\Users\hawkwang>route print
IPv6 Route Table
=============================================================
Active Routes:
 If Metric Network Destination      Gateway
 17    276 ::/0                     fe80::224:dcff:fe16:7403
  1    306 ::1/128                  On-link
 17     28 2001:200::/64            On-link
 17    276 2001:200::10/128         On-link
 17    276 fe80::/64                On-link
 17    276 fe80::390d:c2b5:2db4:45c8/128
                                    On-link
  1    306 ff00::/8                 On-link
 17    276 ff00::/8                 On-link
=============================================================
Persistent Routes:
  None
Notice that the IPv6 default gateway is not 2001:200::1 , but the link address is fe80::224:dcff:fe16:7403%17 . Currently, as per RF C4861 , the DHCPv6 client can obtain the default gateway only from the local address on the DHCPv6 server.