Users on an internal network cannot access Internal servers using domain names. Why

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When a user device accesses the internal server using a domain name, whether the domain name contains the host name varies. Therefore, you have to configure different DNS domain names in the following two situations. For example, you want to access the domain name www.hbjs.gov.cn.

  • When the DNS Request packet sent by the user device contains the host name, that is, the user device uses the domain name www.hbjs.gov.cn to access the internal server, run the nat dns-map www.hbjs.gov.cn global-address global-port { tcp | udp } command.
  • When the DNS Request packet sent by the user device does not contain the host name, that is, the user device uses the domain name hbjs.gov.cn to access the internal server, run the nat dns-map hbjs.gov.cn global-address global-port { tcp | udp } command.

NOTE:

If you are not sure whether the DNS Request packet sent by the device contains the host name or not, it is recommended that you configure both the preceding commands.

Other related questions:
Intranet users cannot access the internal server using a domain name, but they can access the internal server using an IP address
Q: Intranet users cannot access the internal server using a domain name, but they can access the internal server using an IP address. A: Ping the domain name and check whether the public IP address can be parsed. If the IP address cannot be correctly parsed, check whether the account password and DNS information are correct. Configure DDNS software on the PC to check whether the IP address can be parsed. If no error is found in the preceding operations, contact the carrier to check the DDNS server. Check whether the DDNS server synchronizes the updated domain name to the DNS server. The causes are as follows: It is used in the scenario where terminals use PPPoE dial-up. The router runs normally when users can access the internal server using IP addresses. DNS resolution is the first step to access a domain name. Because the PPPoE interface dynamically obtains an IP address from a carrier, the DDNS server must send the updated mapping between the domain name and IP address to the DNS server in real time. Check whether the DDNS server synchronizes the updated domain name to the DNS server.

Configure NAT on the AR router to allow internal hosts to access internal servers using a domain name
If no intranet DNS servers are used and DNS domain names need to be used to access internal servers on an enterprise network, internal users have to send packets carrying DNS domain names to access a DNS server on a public network. A Huawei AR router allows internal and external users to access internal servers through domain names by configuring the NAT server and DNS mapping. The web server uses internal IP address 192.168.0.100/24 and port 8080. The web server has a public address of 202.10.1.3/24 and domain name of www.TestNat.com. The configuration is as follows: 1. Assign IP addresses to interfaces on the router. [Huawei] interface Ethernet0/0/0 [Huawei-Ethernet0/0/0] ip address 192.168.0.1 24 [Huawei-Ethernet0/0/0] quit [Huawei] interface GigabitEthernet2/0/0 [Huawei-GigabitEthernet2/0/0] ip address 202.10.1.2 24 [Huawei-GigabitEthernet2/0/0] quit 2. Configure a default route and specify the next hop address as 202.10.1.1. [Huawei] ip route-static 0.0.0.0 0.0.0.0 202.10.1.1 3. Configure the NAT server and outbound NAT in Easy IP mode on GE2/0/0. [Huawei] acl number 2000 [Huawei-acl-basic-2000] rule 5 permit source 192.168.0.0 0.0.0.255 [Huawei-acl-basic-2000] quit [Huawei] interface GigabitEthernet2/0/0 [Huawei-GigabitEthernet2/0/0] nat server protocol tcp global 202.10.1.3 www inside 192.168.0.100 8080 [Huawei-GigabitEthernet2/0/0] nat outbound 2000 [Huawei-GigabitEthernet2/0/0] quit 4. Enable NAT ALG for DNS and DNS mapping. [Huawei] nat alg dns enable [Huawei] nat dns-map www.testnat.com 202.10.1.3 80 tcp [Huawei] quit

An internal user cannot access the internal server through the public address
An intranet user cannot use a public address to access an intranet server. Use the following method: 1. Check whether services on the intranet NAT server are running properly. 2. Check whether the NAT server is configured correctly. 3. Check the connection between the external host and NAT server and the configurations of the connected interfaces. 4. Check that the intranet NAT server is configured with the correct gateway address or route.

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