Example for Configuring Association Between the DNS Server and NQA
Networking Requirements
As shown in Figure 4-12, Router is the enterprise's gateway device; the PC is the host in the enterprise and is connected to Router through the access switch. At the same time, PC can function as a DNS client to connect to the network using a domain name; Router can function as a DNS proxy to uniformly manage the DNS servers that the enterprise can access. The enterprise can access two DNS servers: Local DNS Server_1 (The mapping between the domain name www.huawei.com and the IP address 10.82.42.59 is recorded) in the local network segment and Remote DNS Server_2 (The mapping between the domain name www.huawei123.com and the IP address 10.46.1.1 is recorded) on the remote end. To improve the domain name resolution efficiency and speed up network access, the enterprise requires that query requests be sent to the DNS servers whose dns function is normal.
Configuration Roadmap
Associate DNS servers with NQA on Router, so that query requests are only sent to the DNS servers whose dns function is normal.
- Configure VLANs for interfaces on the switch to implement Layer 2 transparent transmission.
- Configure the DNS client function on PC so that it can connect to the network using a domain name.
- Configure the DNS proxy function on Router and associate Router with NQA, so that query requests are only sent to the DNS servers whose dns function is normal.
Procedure
- Configure VLANs for interfaces on the switch (using a Huawei S series switch as an example).
<Huawei> system-view [Huawei] sysname Switch [Switch] interface gigabitethernet 0/0/1 [Switch-GigabitEthernet0/0/1] port link-type trunk [Switch-GigabitEthernet0/0/1] port trunk allow-pass vlan 10 [Switch-GigabitEthernet0/0/1] port trunk pvid vlan 10 [Switch-GigabitEthernet0/0/1] quit [Switch] interface gigabitethernet 0/0/2 [Switch-GigabitEthernet0/0/2] port link-type trunk [Switch-GigabitEthernet0/0/2] port trunk allow-pass vlan 10 [Switch-GigabitEthernet0/0/2] port trunk pvid vlan 10 [Switch-GigabitEthernet0/0/2] quit [Switch] interface gigabitethernet 0/0/3 [Switch-GigabitEthernet0/0/3] port link-type access [Switch-GigabitEthernet0/0/3] port default vlan 10 [Switch-GigabitEthernet0/0/3] quit
- Configure the DNS client function on PC.
- Right-click Network and choose Properties to display the Network and Sharing Center window.
- Click Local Area Connection to display the Local Area Connection Status window.
- Click Properties to display the Local Area Connection Properties window.
- Select Internet Protocol Version 4 (TCP/IPv4) and click Properties to display the Internet Protocol Version 4 (TCP/IPv4) Properties window. Select Use the following DNS server addresses, enter the DNS Proxy address 10.1.1.1 in the Preferred DNS server text box, and click OK.
- Configure the DNS proxy function on Router and associate Router with NQA.
<Huawei> system-view [Huawei] sysname Router [Router] dns proxy enable [Router] dns resolve [Router] nqa test-instance admin localdns [Router-nqa-admin-localdns] test-type dns [Router-nqa-admin-localdns] dns-server ipv4 10.1.1.2 [Router-nqa-admin-localdns] destination-address url www.huawei.com [Router-nqa-admin-localdns] frequency 30 [Router-nqa-admin-localdns] start now [Router-nqa-admin-localdns] quit [Router] nqa test-instance admin remotedns [Router-nqa-admin-remotedns] test-type dns [Router-nqa-admin-remotedns] dns-server ipv4 10.20.1.2 [Router-nqa-admin-remotedns] destination-address url www.huawei123.com [Router-nqa-admin-remotedns] frequency 30 [Router-nqa-admin-remotedns] start now [Router-nqa-admin-remotedns] quit [Router] dns server 10.1.1.2 track nqa admin localdns [Router] dns server 10.20.1.2 track nqa admin remotedns [Router] interface gigabitethernet 0/0/1 [Router-GigabitEthernet0/0/1] ip address 10.1.1.1 24 [Router-GigabitEthernet0/0/1] quit [Router] interface gigabitethernet 0/0/2 [Router-GigabitEthernet0/0/2] ip address 10.20.1.1 24 [Router-GigabitEthernet0/0/2] quit
To persistently detect the DNS server status, you need to perform periodical test for NQA test instances. Therefore, run the frequency interval command to set the automatic test interval for NQA test instances.
- Verify the configuration.
# Run the display nqa history test-instance command to check the check result of two test instances, and run the display dns server command to check the states of the two DNS servers. The command output shows that the DNS server state is Up when the NQA check result is success. In this case, dynamic domain name resolution can be performed on the two DNS servers.
[Router] display nqa history test-instance admin localdns NQA entry(admin, localdns) history: Index T/H/P Response Status Address Time 1 61/1/1 19ms success 10.82.42.59 2014-06-23 12:01:50.900 2 62/1/1 19ms success 10.82.42.59 2014-06-23 12:02:20.900 3 63/1/1 24ms success 10.82.42.59 2014-06-23 12:02:50.900 4 64/1/1 20ms success 10.82.42.59 2014-06-23 12:03:20.910 5 65/1/1 15ms success 10.82.42.59 2014-06-23 12:04:19.360 6 66/1/1 13ms success 10.82.42.59 2014-06-23 12:04:49.260
[Router] display nqa history test-instance admin remotedns NQA entry(admin, remotedns) history: Index T/H/P Response Status Address Time 1 63/1/1 16ms success 10.46.1.1 2014-06-23 12:04:10.560 2 64/1/1 5ms success 10.46.1.1 2014-06-23 12:04:40.450 3 65/1/1 5ms success 10.46.1.1 2014-06-23 12:05:10.490 4 66/1/1 5ms success 10.46.1.1 2014-06-23 12:05:40.480 5 67/1/1 5ms success 10.46.1.1 2014-06-23 12:06:10.380 6 68/1/1 6ms success 10.46.1.1 2014-06-23 12:06:40.350
[Router] display dns server Type: D:Dynamic S:Static IPv4 DNS server : NO. Type Status Used IP Address 1 S Up Yes 10.1.1.2 2 S Up Yes 10.20.1.2 IPv6 DNS servers : NO. Type Status Used IPv6 Address Interface
# On Local DNS Server_1, delete the mapping between the domain name www.huawei.com and IP address 10.82.42.59 to simulate the situation in which the DNS server is faulty. Run the display nqa history test-instance command to check the result of two test instances, and run the display dns server command to check the states of the two DNS servers. The command output shows that the NQA check result of Local DNS Server_1 is timeout and the server state is Down. In this case, dynamic domain name resolution is only performed on Remote DNS Server_2.
[Router] display nqa history test-instance admin localdns NQA entry(admin, localdns) history: Index T/H/P Response Status Address Time 1 842/1/1 3000ms timeout unKnown 2014-06-23 18:32:55.240 2 843/1/1 3000ms timeout unKnown 2014-06-23 18:33:25.260 3 844/1/1 3000ms timeout unKnown 2014-06-23 18:33:55.360 4 845/1/1 3000ms timeout unKnown 2014-06-23 18:34:25.390 5 846/1/1 3000ms timeout unKnown 2014-06-23 18:34:55.320 6 847/1/1 3000ms timeout unKnown 2014-06-23 18:35:25.320
[Router] display nqa history test-instance admin remotedns NQA entry(admin, remotedns) history: Index T/H/P Response Status Address Time 1 843/1/1 13ms success 10.46.1.1 2014-06-23 18:34:11.130 2 844/1/1 15ms success 10.46.1.1 2014-06-23 18:34:41.150 3 845/1/1 18ms success 10.46.1.1 2014-06-23 18:35:11.140 4 846/1/1 13ms success 10.46.1.1 2014-06-23 18:35:41.160 5 847/1/1 14ms success 10.46.1.1 2014-06-23 18:36:11.150 6 848/1/1 16ms success 10.46.1.1 2014-06-23 18:36:41.120
[Router] display dns server Type: D:Dynamic S:Static No. Type Status IP Address 1 S Down 10.1.1.2 2 S Up 10.20.1.2 No configured ipv6 dns servers.
Configuration Files
Configuration file of the switch
# sysname Switch # vlan batch 10 # interface GigabitEthernet0/0/1 port link-type trunk port trunk pvid vlan 10 port trunk allow-pass vlan 10 # interface GigabitEthernet0/0/2 port link-type trunk port trunk pvid vlan 10 port trunk allow-pass vlan 10 # interface GigabitEthernet0/0/3 port link-type access port default vlan 10 # return
Configuration file of the router
# sysname Router # dns resolve dns server 10.1.1.2 track nqa admin localdns dns server 10.20.1.2 track nqa admin remotedns dns proxy enable # interface GigabitEthernet0/0/1 ip address 10.1.1.1 255.255.255.0 # interface GigabitEthernet0/0/2 ip address 10.20.1.1 255.255.255.0 # nqa test-instance admin localdns test-type dns destination-address url www.huawei.com frequency 30 dns-server ipv4 10.1.1.2 start now nqa test-instance admin remotedns test-type dns destination-address url www.huawei123.com frequency 30 dns-server ipv4 10.20.1.2 start now # return