Correct an Incomplete DNS Configuration

Troubleshooting › Correct an Incomplete DNS Configuration

Correct an Incomplete DNS Configuration

Issues can arise with TCP/IP computer name configuration. For example, emails can bounce back with an error message indicating an invalid host or CA Gateway Security may be unable to connect to your DNS and SMTP servers even though you have verified that the servers are up and running.

An incomplete DNS configuration is usually the cause. For CA Gateway Security to relay emails using MX, the TCP/IP host name on your computer must exist on your DNS server. Also, the TCP/IP addresses that your computer uses must themselves have names. This means that you need both forward and reverse DNS lookups installed on your system.

To correct an incomplete DNS configuration, follow these steps:

Check the host name/domain name that is set in your TCP/IP configuration. Verify that you can ping this full name, both from your computer and from another computer. You must have a DNS entry for your computer on your DNS server.

If you have multiple TCP/IP addresses, make sure that the first TCP/IP address on your system has a DNS name entry.

Using the program nslookup.exe (nslookup on UNIX computers), check if the DNS entries are set up correctly. For example, if your computer is named mail.company.com, enter the following:

nslookup mail.company.com

The nslookup should respond as follows:

Server:  imdns.company.com (This is your DNS server name.)
Address:  194.90.1.5 (This is your DNS server address.)
Name:    mail.company.com (This is your host name.)
Address:  194.90.18.5 (This is your TCP/IP address.)

If your DNS is not set up correctly, nslookup may respond as follows:

*** imdns.company.com can't find mail.company.com: Non-existent host/domain

or nslookup may respond as follows:

Server:  imdns.company.com
Address:  194.90.1.5 
DNS request timed out.
    timeout was 2 seconds.
*** Request to imdns.company.com timed-out

If the DNS problem still occurs and you did not receive an error message, invoke a reverse lookup action by entering the TCP/IP address of your computer. For example, if the TCP/IP address of your computer is 194.90.18.5, enter the following:
```
nslookup 194.90.18.5
```
If your DNS is not set up correctly, reverse lookup may respond as follows:
```
*** imdns.company.com can't find 194.90.18.5: Non-existent host/domain
```
or nslookup may respond as follows:
```
Server:  imdns.company.com
Address:  194.90.1.5 
DNS request timed out.
    timeout was 2 seconds.
*** Request to imdns.company.com timed-out
```
If you have a DNS problem, contact the system administrator or your ISP provider responsible for your DNS.