N1548 as a DHCPv6 relay

Question

Hello everybody,

Was anybody able to set N1548 to work as a DHCPv6 relay? DHCPv4 works fine for me but it looks like DHCPv6 requests do not propagate through the switch. Here is my partial config of the switch:

ipv6 unicast-routing
ip routing
ip dhcp relay information option
ip helper-address 10.20.1.71

interface vlan 7
ip address 10.20.7.1 255.255.255.0
ip helper-address 10.20.1.71
ipv6 address 2001:db8:acad:2007::1/64
ipv6 enable
ipv6 dhcp relay destination 2001:db8:acad:2040::71
ip dhcp relay information option-insert
exit

interface vlan 20
ip address 10.20.20.3 255.255.255.0
ipv6 address 2001:db8:acad:2020::3/64
exit

ip default-gateway 10.20.20.1

ip dhcp snooping
ip dhcp snooping vlan 7
ipv6 dhcp snooping
ipv6 dhcp snooping vlan 7

interface Gi1/0/5
description "TEST"
spanning-tree portfast
spanning-tree guard root
switchport access vlan 7
exit

interface Gi1/0/9
ip dhcp snooping trust
ipv6 dhcp snooping trust
description "RT GE 0/0"
spanning-tree guard root
switchport mode trunk
switchport trunk allowed vlan 1,10,20,...
exit

ipv6 route ::/0 Vl20 fe80::1

DHCPv6 server is accessible:

SWITCH1#ping ipv6 2001:db8:acad:2040::71
Reply From 2001:db8:acad:2040::71 icmp_seq = 0. time= 1 msec.
Reply From 2001:db8:acad:2040::71 icmp_seq = 1. time= 1 msec.
Reply From 2001:db8:acad:2040::71 icmp_seq = 2. time= 1 msec.
Reply From 2001:db8:acad:2040::71 icmp_seq = 3. time= 1 msec.

Pinging 2001:db8:acad:2040::71 with 0 bytes of data:

Send count=4, Receive count=4 from 2001:db8:acad:2040::71
Average round trip time = 1.00 ms

Client is sending DHCPv6 solicits:

17:45:59.783117 IP6 fe80::bb65:e12f:4361:6396.546 > ff02::1:2.547: dhcp6 solicit
17:46:03.898007 IP6 fe80::bb65:e12f:4361:6396.546 > ff02::1:2.547: dhcp6 solicit
17:46:11.978889 IP6 fe80::bb65:e12f:4361:6396.546 > ff02::1:2.547: dhcp6 solicit
17:46:27.425233 IP6 fe80::bb65:e12f:4361:6396.546 > ff02::1:2.547: dhcp6 solicit

But no packets are coming out of the switch towards DHCPv6 server.

SLAAC is working fine and there is no problem with IPv6 connectivity in general.

Switch firmware is the latest: 6.3.3.8, but behaviour was the same on older versions.

Any input is highly appreciated.

Thanks,

Dmytro

DELL-Josh Cr · Answer

Hi, What does show ipv6 dhcp statistics show?

gaucho2015 · Answer

Hi Josh,

There is no such command in this firmware:

SWITCH1#show ipv6 dhcp statistics
                                  ^
% Invalid input detected at '^' marker.

SWITCH1#show ipv6 dhcp ?


  
    Press enter to execute the command. | Output filter options. snooping Display DHCPv6 snooping configuration. SWITCH1#show ipv6 ? access-lists Display access list information. brief Display IPv6 summary. dhcp Display IPv6 DHCP info. interface Display IPv6 interface information. mld Display MLD router info. nd Show IPv6 Neighbor discovery. neighbors Display IPv6 neighbors. prefix-list Display router prefix-list information. route Display IPv6 route information. snooping Show IPv6 RA GUARD. source Display IPv6 source guard bindings. traffic Display IPv6 traffic statistics. verify Display IPv6 source guard information. vlan Display IPv6 Vlan statistics. SWITCH1#show dhcp ? l2relay Display DHCP L2 Relay configuration. lease Display DHCP client lease parameters. SWITCH1#
   

   

   Thanks,
   

   Dmytro

gaucho2015 · Answer

Just in case a few more commands:

SWITCH1#show ipv6 dhcp snooping

DHCPv6 snooping is Enabled
DHCPv6 snooping source MAC verification is disabled
DHCPv6 snooping is enabled on the following VLANs:
7

 Interface    Trusted     Log Invalid Pkts
-----------  ----------   ----------------
Gi1/0/5      No           No
Po1          No           No
Po2          Yes          No
Po3          No           No


SWITCH1#show ipv6 dhcp snooping statistics

Interface  MAC Verify   Client Ifc   DHCP Server
           Failures     Mismatch     Msgs Rec'd
---------- ------------ ------------ ------------
Gi1/0/5    0            0            0
Po1        0            0            0
Po3        0            0            0

Test PC is connected to port Gi1/0/5.

Thanks,
Dmytro

DELL-Josh Cr · Answer

Can you private message me the service tag?

gaucho2015 · Answer

Josh, Sure, sent a minute ago. Thanks,Dmytro

DELL-Josh Cr · Answer

Thanks, try show ipv6 dhcp traffic.

gaucho2015 · Answer

Josh,

This command is not supported:


SWITCH1#show ipv6 dhcp traffic
                                 ^
% Invalid input detected at '^' marker.

SWITCH1#show ipv6 dhcp ?


  
    Press enter to execute the command. | Output filter options. snooping Display DHCPv6 snooping configuration. SWITCH1#show ipv6 dhcp DHCPv6 is disabled Server DUID: 00:01:00:06:a4:e6:d4:36:14:18:77:ea:f3:ec SWITCH1#show version Machine Description............... Dell Networking Switch System Model ID................... N1548 Machine Type...................... Dell Networking N1548 Serial Number..................... * Manufacturer...................... 0xbc00 Burned In MAC Address............. 1418.77EA.F3EC System Object ID.................. 1.3.6.1.4.1.674.10895.3065 SOC Version....................... BCM56150_A0 HW Version........................ 2 CPLD Version...................... 16 unit active backup current-active next-active ---- ----------- ----------- -------------- -------------- 1 6.3.3.8 6.3.2.7 6.3.3.8 6.3.3.8

Thanks,

Dmytro

DELL-Josh Cr · Answer

That is odd it shows the command in the list of commands you had when show ipv6 dhcp statistics didn’t work.

gaucho2015 · Answer

Josh, There is no such command as 'show ipv6 dhcp traffic' but there is another one: SWITCH1#show ipv6 traffic IPv6 STATISTICS Total Datagrams Received.................................. 9 Received Datagrams Locally Delivered...................... 6 Received Datagrams Discarded Due To Header Errors......... 0 Received Datagrams Discarded Due To MTU................... 0 Received Datagrams Discarded Due To No Route.............. 0 Received Datagrams With Unknown Protocol.................. 0 Received Datagrams Discarded Due To Invalid Address....... 0 Received Datagrams Discarded Due To Truncated Data........ 0 Received Datagrams Discarded Other........................ 0 Received Datagrams Reassembly Required.................... 0 Datagrams Successfully Reassembled........................ 0 Datagrams Failed To Reassemble............................ 0 Datagrams Forwarded....................................... 0 Datagrams Locally Transmitted............................. 6 Datagrams Transmit Failed................................. 0 Datagrams Successfully Fragmented......................... 0 Datagrams Failed To Fragment.............................. 0 Fragments Created......................................... 0 Multicast Datagrams Received.............................. 3 Multicast Datagrams Transmitted........................... 0 ICMPv6 STATISTICS Total ICMPv6 Messages Received............................ 6 ICMPv6 Messages With Errors Received...................... 0 ICMPv6 Destination Unreachable Messages Received.......... 0 ICMPv6 Messages Prohibited Administratively Received...... 0 ICMPv6 Time Exceeded Messages Received.................... 0 ICMPv6 Parameter Problem Messages Received................ 0 ICMPv6 Packet Too Big Messages Received................... 0 ICMPv6 Echo Request Messages Received..................... 0 ICMPv6 Echo Reply Messages Received....................... 0 ICMPv6 Router Solicit Messages Received................... 0 ICMPv6 Router Advertisement Messages Received............. 0 ICMPv6 Neighbor Solicit Messages Received................. 3 ICMPv6 Neighbor Advertisement Messages Received........... 3 ICMPv6 Redirect Messages Received......................... 0 ICMPv6 Group Membership Query Messages Received........... 0 ICMPv6 Group Membership Response Messages Received........ 0 ICMPv6 Group Membership Reduction Messages Received....... 0 Total ICMPv6 Messages Transmitted......................... 6 ICMPv6 Messages Not Transmitted Due To Error.............. 0 ICMPv6 Destination Unreachable Messages Transmitted....... 0 ICMPv6 Messages Prohibited Administratively Transmitted... 0 ICMPv6 Time Exceeded Messages Transmitted................. 0 ICMPv6 Parameter Problem Messages Transmitted............. 0 ICMPv6 Packet Too Big Messages Transmitted................ 0 ICMPv6 Echo Request Messages Transmitted.................. 0 ICMPv6 Echo Reply Messages Transmitted.................... 0 ICMPv6 Router Solicit Messages Transmitted................ 0 ICMPv6 Router Advertisement Messages Transmitted.......... 0 ICMPv6 Neighbor Solicit Messages Transmitted.............. 3 ICMPv6 Neighbor Advertisement Messages Transmitted........ 3 ICMPv6 Redirect Messages Transmitted...................... 0 This is output shortly after client interface went up and sent SOLICIT Thanks,Dmytro

DELL-Josh Cr · Answer

So it looks like it thinks it is transmitting messages.

gaucho2015 · Answer

Josh,

No packets are exiting the switch towards DHCP server. I configured port mirroring for outbound interface of the switch and this is what I see:

IPv6 ping of DHCP server from the switch is successful
If I use SLAAC to configure on test PC it is also able to ping DHCP server via IPv6
If I try to obtain IPv6 address from DHCP then solicit packets are entering the switch but they do not appear on exit towards DHCP server

Thanks,
Dmytro

gaucho2015 · Answer

Josh,

Do you have any ideas so far?

I just tried to assemble another lab with a separate N1548 dedicated for testing DHCPv6 relaying. I also was not capable to make it work -- no requests are reaching DHCPv6 server directly connected to the switch's outbound interface.

I have to conclude that this switch model is not capable of DHCPv6 relay function.

Thanks,
Dmytro

DELL-Josh Cr · Answer

I have not found anything and since you don’t have a Prosupport contract there isn’t software troubleshooting from warranty support.

Networking General

N1548 as a DHCPv6 relay

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