04-14-2021 11:59 PM
Hi All,
Currently trying to test DHCP on QinQ Sub-Interfaces on an ASR 1001-X. Static Addressing works without a hitch, but when setting the sub-interface with the DHCP Pool Default-Router address to enable a remote router to obtain an IP Address via DHCP, the 'dhcp server' receives the DHCPDISCOVER message but nothing appear to be sent to the remote router. I have included DHCP Pool, sub-interface configurations below along with 'sh ip dhcp server statistics' output and
. I would appreciate any and all advice on what I am missing!
no ip domain lookup
ip dhcp excluded-address 103.xxx.xxx.233
!
ip dhcp pool RC_Trial
network 103.xxx.xxx.232 255.255.255.248
dns-server 8.8.8.8 8.8.4.4
default-router 103.xxx.xxx.233
domain-name xxxxx.com.au
lease 8
INTERFACE
interface GigabitEthernet0/0/3.30x
description xxxxxxx
encapsulation dot1Q 30xx second-dot1q 35xx
ip address 103.xxx.xxx.233 255.255.255.252
ip access-group ACL-DHCP-Allow out
ip access-list extended ACL-DHCP-Allow
permit udp any host 255.255.255.255 eq bootps bootpc
permit ip any any
'SH IP DHCP SERVER STATISTICS' Output
Memory usage 20550
Address pools 2
Database agents 0
Automatic bindings 0
Manual bindings 0
Expired bindings 0
Malformed messages 2533
Secure arp entries 0
Renew messages 0
Workspace timeouts 0
Static routes 0
Relay bindings 0
Relay bindings active 0
Relay bindings terminated 0
Relay bindings selecting 0
Message Received
BOOTREQUEST 0
DHCPDISCOVER 2512
DHCPREQUEST 20
DHCPDECLINE 0
DHCPRELEASE 0
DHCPINFORM 0
DHCPVENDOR 0
BOOTREPLY 0
DHCPOFFER 0
DHCPACK 0
DHCPNAK 0
Message Sent
BOOTREPLY 0
DHCPOFFER 0
DHCPACK 0
DHCPNAK 0
Message Forwarded
BOOTREQUEST 0
DHCPDISCOVER 0
DHCPREQUEST 0
DHCPDECLINE 0
DHCPRELEASE 0
DHCPINFORM 0
DHCPVENDOR 0
BOOTREPLY 0
DHCPOFFER 0
DHCPACK 0
DHCPNAK 0
DHCP-DPM Statistics
Offer notifications sent 0
Offer callbacks received 0
Classname requests sent 0
Classname callbacks received 0
Edge.TR.M1#sh ip sockets
Proto Remote Port Local Port In Out Stat TTY Output IF
17 103.xxx.xxx.134 50149 103.xxx.xxx.130 161 0 0 2001001 0
17 --listen-- 110.xxx.xxx.50 162 0 0 2001011 0
17 --listen-- 110.xxx.xxx.50 53998 0 0 2001011 0
17(v6) --listen-- --any-- 161 0 0 2020001 0
17(v6) --listen-- --any-- 162 0 0 2020011 0
17(v6) --listen-- --any-- 49477 0 0 2020001 0
17 103.xxx.xxx.134 514 103.xxx.xxx.65 51381 0 0 400210 0
17 0.0.0.0 0 --any-- 67 0 0 2002211 0
Solved! Go to Solution.
04-21-2021 05:00 PM
Craig
Thanks for the update. Glad to know that it is now working for you. My guess is that specifying the option 82 information was more significant but it is certainly possible that Paul's suggestion for trust all was also helpful. The important thing is that now it is working for you.
04-15-2021 12:38 AM
Hello
With the encapsulation on the subinterface it is now being tagged -
so if the device that connects to the physical interface of your rtr is a switch then that port needs to be a trunk and be able to accept vlan 30 or if it’s a rtr it needs to be in the same sub interface
04-15-2021 04:01 AM
04-15-2021 09:32 AM
Craig
I do not understand your statement "There is no possibility of the remote router being a member of any VLAN." Paul makes a good point that your subinterface will be sending Ethernet frames tagged with vlan ID. So the remote router needs to process tagged Ethernet frames. If the router is not a member of any vlan will it process tagged frames?
Perhaps you can give us some information about the remote router and how it is configured?
04-15-2021 12:40 PM
04-15-2021 02:44 PM
Craig
Thanks for the clarification. My experience with QinQ has not been that tags were removed before delivery to the remote router. But if that is happening in your network then we need to look for some other issues.
To make sure that I am understanding correctly - if you keep the sub interface QinQ configuration and manually configure IP addresses on both sides then there is successful communication? That would certainly indicate that the issue is about DHCP. Perhaps debug for DHCP might shed some light on the issue.
04-15-2021 08:03 PM
04-19-2021 07:16 PM
04-20-2021 12:06 AM
Craig
Thanks for the debug output. There are messages that I am not clear about but that certainly do show that there is some problem with the configuration. One of those messages is
Apr 20 00:13:27.866: DHCPD: inconsistent relay information.
I am not sure about it but I wonder if it relates to the fact that your DHCP pool describes a network with mask 255.255.255.248 but the mask of the interface is different
ip address 103.xxx.xxx.233 255.255.255.252
I am also not clear about this message
Apr 20 00:13:27.866: DHCPD: relay information option exists, but giaddr is zero
giaddr is the gateway address in the DHCP request and is typically used when the DHCP request is being sent to a server whose IP address is in a subnet different from the subnet where the client is. If the remote router and your router are in the same subnet then I am not sure why the relay information option is used but the DHCP request has giaddr as zero. That would seem to reflect some issue on the remote router request.
I suggest changing the interface mask in the configuration to be consistent with the mask in the DHCP pool. If that does not resolve the issue then I believe that we need to find some information about the configuration of the remote router.
04-20-2021 02:25 AM
Hello
@claurie wrote:
Hi Richard,
*Apr 20 00:13:27.866: DHCPD: inconsistent relay information.
*Apr 20 00:13:27.866: DHCPD: relay information option exists, but giaddr is zero.
Try enabling dhcp to trust packets with a zero gateway-address
ip dhcp relay information trust-all
04-20-2021 07:16 PM
04-21-2021 05:00 PM
Craig
Thanks for the update. Glad to know that it is now working for you. My guess is that specifying the option 82 information was more significant but it is certainly possible that Paul's suggestion for trust all was also helpful. The important thing is that now it is working for you.
06-23-2021 02:58 AM
Hi
Sorry does anyone know how to find a cisco document for configuring the BNG/BRAS with IPOE in ASR1002 - IOS XE??
thanks in advance
06-23-2021 05:51 PM
04-21-2021 05:03 PM
Thank You Both
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