Device Configuration : Protect : Add Business Application Rule (Web Server Protection (WAF)) : Email Servers (SMTP)
Email Servers (SMTP)
This page allows you to configure rule for Email Servers (SMTP).
1. Click Policies and select among IPv4 or IPv6 using the filter switch. Now, click on +Add Firewall Policy and select Business Application Rule.
2. Enter policy introduction for About This Rule.
Application Template
Select Email Servers (SMTP) to configure rule for SMTP based Email applications.
Description
Specify Policy Description.
Rule Position
Specify the position of the rule.
Available Options:
* Top
* Bottom
* Rule Position can only be specified while creating a rule.
Rule Name
Specify a name to identify the policy.
* Rule Name can only be edited while creating a rule.
3. Specify Source details.
Source Zones
Click to select the source zone. Click Add New Item to define a new LAN or DMZ zone
Allowed Client Networks
Select the allowed host(s) or add a new one by clicking Add New Item.
Blocked Client Networks
Select the blocked host(s)/network(s).
4. Specify Destination & Service details.
Firewall Version
Choose from the following options:
Available Options:
* Firewalls running on SFOS v17
* Firewalls running on SFOS v16.x
Destination Host/Network
Select the destination host/network to apply rule. It is the public IP address through which users access internal server/host over the Internet.
Available Options:
* IP Address – Specified IP address is mapped to a corresponding mapped single or range of IP addresses. If a single IP address is mapped to a range of IP addresses, the device uses a sticky IP algorithm to load balance the requests.
* IP Range – Specified IP address range is mapped to a corresponding range of mapped IP addresses. The IP range defines the start and end of an address range. The start of the range must be lower than the end of the range.
* Interface IP (only available for IPv4) – Select when any of the device port, alias or virtual LAN (VLAN) sub interface is required to be mapped to the destination host or network.
Services
Select the services allowed to the user. A new service can be directly created from this page.
Add new item
Name: Enter a name to identify the service.
Type: Select a protocol for the service.
Available Options:
* TCP/UDP: Enter Source and Destination port. You can enter multiple ports for the same service. The number of source and destination ports must not exceed 16.
* IP: Select Protocol Number for the service. You can select multiple ports for the same service.
* ICMP: Select ICMP Type and Code. You can enter multiple types and codes for the same service. Use Add icon and Remove icon to add and delete the parameters respectively.
* ICMPv6: Select ICMPv6 Type and Code. You can enter multiple types and codes for the same service. Use Add and Remove to add and delete the parameters.
Forward Type
Select the type of external port from the available options.
Available Options:
* Port
* Port Range
* Port List
* Everything
When Everything is selected, all ports are forwarded. Select other options to enable custom port forwarding and specify port forwarding details.
Service Port(s) Forwarded (Not Available if Forward Type selected is Everything)
Specify the public port number for which you want to configure port forwarding.
Protocol (Not Available if Forward Type selected is Everything)
Select the protocol TCP or UDP to be used by forwarding packets.
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5. Specify Forward To details.
Protected Server(s)
Select from the available options on which the email server is to be hosted.
Available options:
* IP Address – External IP address is mapped to the specified IP address.
* IP Range – External IP address range is mapped to the specified IP address range.
* IP List – External IP address is mapped to the specified IP list.
* FQDN (available only for IPv4 virtual hosts) – External IP address is mapped to the specified FQDN. Internal mapped server can be accessed by FQDN.
* For IP Range and IP List, you can also use a single external IP address. The device will then use load balancing for handling the requests.
Mapped Port Type (Available only if Change Destination Port(s) is selected)
Select the type of mapped port from the available options.
Available Options:
* Port
* Port Range
* Port List
* Not applicable for firewalls running on SFOS v17.
Mapped Port (available only if Change Destination Port(s) is selected)
Specify mapped port number on the destination network to which the public port number is mapped. Mapped port must have the same number of ports as specified in the public service, or at least have one port. Mapped Port is disabled if:
No TCP/UDP service is selected.
Multiple services are selected.
Service group is selected.
Selected service is with TCP/UDP combination.
Protected Zone
Select the zone to which the email server rule applies.
Change Destination Port(s)
Select the check box to specify different mapped port. Clear the check box to use the same Service Port(s) Forwarded as mapped port.
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6. Specify Load Balancing details.
Load Balancing (Applicable when 'IP Range' or 'IP List' is selected for Protected Server. Also, Source Zone for Hosted Server should be 'WAN')
Select the method for load balancing from the available options.
Available Options
Round Robin - In this method, requests are served in a sequential manner where the first request is forwarded to the first server, second request to the second server and so on. When a request is received, the device checks to see which the last server that was assigned a request was. It then assigns this new request to the next available server. This method is can be used when equal distribution of traffic is required and there is no need for session-persistence.
First Alive - In this method, all incoming requests are served by the first server (the first IP Address that is configured in the IP Range). This server is considered as the primary server and all others are considered as backup. Only when the first server fails, the requests are forwarded to the next server in line. This method is used for failover scenarios.
Random -In this method, the requests are forwarded to the servers randomly. Although, the device makes sure that all configured servers receive equally distributed load. Hence, this method is also called uniform random distribution. This method can be used when equal distribution of traffic is required and there is no need for session-persistence or order of distribution.
Sticky IP - In this method, Along with Round Robin distribution of traffic, the device forwards incoming traffic according to the Source IP Address. All traffic from a particular source is forwarded only to its mapped Server. This means that all requests for a given source IP are sent to the same application server instance. This method is useful in cases where all requests or sessions are required to be processed by the same server. For example: Banking websites, E-Commerce websites.
Health Check (Applicable if Load Balancing is enabled)
Click to enable health check for failover and specify the parameters based on the description shown below.
Probe Method
Select the probe method to check the health of the server from the available options.
Available Options:
TCP Probe
ICMP Probe
Port (Applicable if TCP Probe Health Check Method is selected)
Specify the Port number on the server health is monitored.
Acceptable Range - 1 to 65535
Interval
Specify the time interval in seconds after which the health will be monitored.
Acceptable Range (Seconds) - 5 to 65535
Default - 60
Timeout
Specify the time interval in seconds within which the server must respond.
Acceptable Range (Seconds) - 1 to 10
Default - 2
Retries
Specify the number of tries to probe the health of the server, after which the server will be declared unreachable
Acceptable Range - 1 to 10
Default – 3
7. Specify Identity details.
Match known users
Match known users allows you to check whether the specified user/user group from the selected zone is allowed to access the selected service or not.
Click to attach the user identity.
Show Captive Portal to unknown users
Select the check box to accept traffic from unknown users. Captive portal page is displayed to the user where the user can login to access the Internet.
Clear the check box to drop traffic from unknown users.
User or Groups (available only if Match known users is enabled)
Select the user(s) or group(s) from the list of available options.
Exclude this user activity from data accounting (available only if Match known users is enabled)
Click to enable/disable user traffic activity from data accounting.
By default, user’s network traffic is considered in data accounting. Select to exclude certain traffic from user data accounting. The traffic allowed through this firewall rule will not be accounted towards data transfer for the user.
8. Specify Scanning details.
Scan SMTP
Click to enable/disable scanning of SMTP traffic.
Scan SMTPS
Click to enable/disable scanning of SMTPS traffic.
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9. Specify Advanced settings details.
a. Specify Polices for Business Applications.
Intrusion Prevention
Select the required IPS policy. If Match rule based on user identity is enabled, user’s IPS policy will be applied automatically, but will not be effective till the respective module is subscribed.
A new IPS policy can be created directly from this page or from the Protect > Intrusion Prevention > IPS Policies page.
Traffic Shaping Policy (not available if Match known users is selected)
Select the required IPS policy. If Match rule based on user identity is enabled, user’s QoS policy will be applied automatically.
A new traffic shaping policy can be created directly from this page or from the System > Profiles > Traffic Shaping page.
b. Specify Security Heartbeat settings (available only if IPv4 is selected).
Minimum Source HB Permitted
Select a minimum health status that a source device must have to conform to this rule. Health status can be either Green, Yellow or No Restriction. If the health criterion is not met, access and privileges defined in this rule will not be granted to the user.
Block clients with no heartbeat
Heartbeat-capable devices can be required to send information on their health status in defined intervals - this is called a heartbeat.
Based on that information, you can restrict a source device’s access to certain services and networks.
Enable/disable the option to require the sending of heartbeats.
Minimum Destination HB Permitted (not available if Protected Zone selected is WAN)
Select a minimum health status that a destination device must have to conform to this rule. Health status can be either Green, Yellow or No Restriction. If the health criterion is not met, access and privileges defined in this rule will not be granted to the user.
Block request to destination with no heartbeat (not available if Protected Zone selected is WAN)
Heartbeat-capable devices can be required to send information on their health status in defined intervals - this is called a heartbeat.
Based on that information, you can block requests to destinations not sending heartbeat.
Enable/disable the option to require the sending of heartbeats.
c. Specify Routing details.
Rewrite source address (Masquerading)
Enable/disable to re-write the source address or specify a NAT policy.
Use Outbound Address (available only if Rewrite source address is enabled)
Select the NAT policy to be applied from the list of available NAT policies.
A new NAT policy can be created directly from this page or from the System > Profiles > Network Address Translation page.
The default NAT policy is Masquerade.
MASQ (Interface Default IP): IP Address of the selected Protected Zone as configured in Configure > Network > Interfaces will be displayed instead of (Interface Default IP).
Create Reflexive Rule
Select ON to automatically create a reflexive firewall rule for the protected host.
The reflexive rule has the same policies as those configured for the hosted server but instead of source zone to destination zone, this rule is applicable on traffic from destination zone to source zone.
By default, the reflexive rule is not created.
10. Specify the logging option for the user application traffic.
Log Firewall Traffic
Click to enable logging of permitted and denied traffic.