NetComm NB712 Filtering Rule for Smtp connection, Filtering rule will be configured as follow

Filtering Rule for SMTP connection

Filtering rule will be configured as follow

Index	Protocol	Direction	Action	Source	Destination	Dest. Port	Schedule
1	TCP	Inbound	Permit	External	Internal	25	Always
2	TCP	Outbound	Permit	Internal	External	>1023	Always
3	TCP	Outbound	Permit	Internal	External	25	Always
4	TCP	Inbound	Permit	External	Internal	>1023	Always
5	Any	Either	Deny	Any	Any	Any	Always

Packet	Direction	Source	Destination	Protocol	Dest. Port	Action (Rule)
1	Inbound	192.168.3.4	172.16.1.1	TCP	25	Permit (A)
2	Outbound	172.16.1.1	192.168.3.4	TCP	1234	Permit (B)

Packet	Direction	Source	Destination	Protocol	Dest. Port	Action (Rule)
3	Outbound	172.16.1.1	192.168.3.4	TCP	25	Permit (C)
4	Inbound	192.168.3.4	172.16.1.1	TCP	1357	Permit (D)

Packet	Direction	Source	Destination	Protocol	Dest. Port	Action (Rule)
5	Inbound	10.1.2.3	171.16.3.4	TCP	6000	Deny (E)
6	Outbound	171.16.3.4	10.1.2.3	TCP	5150	Deny (E)

NB712 /	NB714 User Guide	53
YML829	Rev1