Description
The customer reported that the router which was configured via DHCP cannot obtain the IP address from the ISP. The topology as below:
Analysis
1. Checked the configuration on the edge router; found that on the interface which connects to the ISP, the configuration was normal.
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[Huawei]dis cu int g0/0/0
#
interface GigabitEthernet0/0/0
ip address dhcp-alloc
#
return
[Huawei]
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2. Checked the DHCP statistics:
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[Huawei]dis dhcp statistics
Input: total 950 packets, discarded 0 packets
Bootp request : 0, Bootp reply : 0
Discover : 378, Offer : 286
Request : 378, Ack : 286
Release : 0, Nak : 0
Decline : 0, Inform : 0
Output: total 865 packets, discarded 0 packets
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From the result, we can learn that the router is not only working as a DHCP client which should obtain the IP address from the ISP, but also working as a DHCP server which allocates the IP address to the internal area users.
3. Checked the DHCP configuration on the edge router:
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[Huawei]dis ip poo
Pool-name : 1
Pool-No : 0
Position : Local Status : Unlocked
Gateway-0 : 10.1.1.1
Mask : 255.255.255.0
VPN instance : --
IP address Statistic
Total :253
Used :1 Idle :252
Expired :0 Conflict :0 Disable :0
[Huawei]
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After confirming with the ISP, we found that the IP pool configured on the edge router is conflicted with the ip pool which configured on the ISP.
Root cause:
The IP pool configured on the edge router conflicts with the IP pool which configured on the ISP.
Solution:
Reconfigure the IP pool on the edge router to another network segment; after that the edge router could obtain the IP address from the ISP.
