[JUNIPER] How to add static DNS mappings in SRX

Summary:

This article provides information on how to add static DNS mappings in SRX.

Symptoms:

The requirement is to add static DNS mappings; for example, if you want www.abc.com, no DNS requests should be sent to a DNS server and it should automatically be resolved to an IP address (for example, 1.1.1.1).

Cause:

 

Solution:
There are a couple ways to achieve this:

Add host to /etc/hosts file

To add the static DNS mappings, modify the /etc/hosts file on the SRX device as follows:

  1. Go to the shell:
    [email protected]> start shell
  2. Edit  the /etc/hosts file via the VI editor:
    [email protected]% vi /etc/hosts
  3. Press i to enter the insert mode and add the following entry:
    1.1.1.1 www.abc.com
  4. Type : wq to save the file.

Then, when you try to ping www.abc.com, SRX will automatically ping 1.1.1.1:

[email protected]# run ping www.abc.com
PING www.abc.com (1.1.1.1): 56 data bytes



Use static-host-mapping

Another method is to add an alias to an IP address using the static-host-mapping option:

root# set system static-host-mapping DPT inet 1.1.1.1
root# set system static-host-mapping DPT alias abc.com
root# commit

You can also add host-name to an IP address:

root# set sysyem static-host-mapping www.abc.com inet 1.1.1.1
root# commit

root# run ping abc.com
PING abc.com (1.1.1.1): 56 data bytes
64 bytes from 1.1.1.1: icmp_seq=0 ttl=57 time=31.675 ms
64 bytes from 1.1.1.1: icmp_seq=1 ttl=57 time=31.133 ms
64 bytes from 1.1.1.1: icmp_seq=2 ttl=57 time=31.152 ms
^C
--- abc.com ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max/stddev = 31.133/31.320/31.675/0.251 ms

For more information, refer to the Related Links below.

 

Fonte: https://kb.juniper.net/InfoCenter/index?page=content&id=KB26800

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