By default, there is a set of predefined firewall rules that can be enabled/disabled for the ESXi host from the vSphere Client.

These firewall services can be enabled/disabled for the defined ports (UDP/TCP) from the vSphere Client. However, if you need to enable the service on a protocol that is not defined, you must create new firewall rules from the command line.

For example, the DNS Client service can be enabled/disabled only on UDP port 53.

To enable DNS for TCP:
 

1. Open an SSH connection to the host. For more information, see Using ESXi Shell in ESXi 5.0 (2004746).
    
2. List the firewall rules by running the command:

   Note: On the vSphere Client, the DNS service is open on port 53 for UDP only.

   
    

To enable the DNS service on port 53 for TCP:

1. Back up the /etc/vmware/firewall/service.xmlfile by running the command:
    
2. Modify the access permissions of the service.xmlfile to allow writes by running the chmodcommand:

   To allow writes:

   To toggle the sticky bit flag:

   # chmod +t /etc/vmware/firewall/service.xml

   
    
3. Open the service.xmlfile in a text editor.
    
4. Add this rule to the service.xmlfile:

   <service id="0032">
<id>DNSTCPOut</id>
<rule id='0000'>
<direction>outbound</direction>
<protocol>tcp</protocol>
<porttype>dst</porttype>
<port>53</port>
</rule>
<enabled>true</enabled>
<required>false</required>
</service>

   Rule set configuration file example:

   <ConfigRoot>
<service id='0000'>
<id>serviceName</id>
<rule id = '0000'>
<direction>inbound</direction>
<protocol>tcp</protocol>
<porttype>dst</porttype>
<port>80</port>
</rule>
<rule id='0001'>
<direction>inbound</direction>
<protocol>tcp</protocol>
<porttype>src</porttype>
<port>
<begin>1020</begin>
<end>1050</end>
</port>
</rule>
<enabled>true</enabled>
<required>false</required>
</service>
</ConfigRoot>

   For more information, see the Rule Set Configuration Files section of the vSphere 5.0 Security Guide.

   
    
5. Revert the access permissions of the service.xmlfile to the read-only default by running the command:

   # chmod 444 /etc/vmware/firewall/service.xml

   
    
6. Refresh the firewall rules for the changes to take effect by running the command:

   # esxcli network firewall refresh

   or

   # localcli network firewall refresh

   Note: This setting does not persist after a reboot. To make it persist, see Changing the port used by SSH on an ESXi 5.0 host (2011818).

   
    
7. List the rules again to confirm by running the command:

   # esxcli network firewall ruleset list

   Name            Enabled
--------------  -----------------
sshServer       true
sshClient       false
nfsClient       true
dhcp            true
dns             true
snmp            true
ntpClient       false
CIMHttpServer   true
CIMHttpsServer  true
CIMSLP          true
iSCSI           true
DNSTCPOut       true

Notes:

• The new DNSTCPOutfirewall rule allows outgoing connections on TCP port 53. New firewall rules and services are also viewable under the Host Configuration section in Security Profile using the vSphere Client.
• ESXi 5.0 Update 1 (build 623860) has a built-in outbound DNS Client running on port 53 (TCP/UDP), which is enabled by default. No action is required to configure DNS client if you are using ESXi 5.0 Update 1.