Packet Filtering
Applies To: Windows Server 2008
Packet filtering
Routing and Remote Access supports IP packet filtering, which specifies which type of traffic is allowed into and out of the router. The packet filtering feature is based on exceptions. You can set packet filters per interface and configure them to do one of the following:
Pass through all traffic except packets prohibited by filters.
Discard all traffic except packets allowed by filters.
Adding a packet filter
To add a packet filter
Open Routing and Remote Access.
In the console tree, click General.
Where?
- Routing and Remote Access/server name/[IPv4 or IPv6]/General
In the details pane, right-click the interface on which you want to add a filter, and then click Properties.
On the General tab, click either Inbound Filters or Outbound Filters.
In the Inbound Filters or Outbound Filters dialog box, click New.
In the Add IP Filter dialog box, type the settings for the filter, and then click OK.
In Filter action, select the appropriate filter action, and then click OK.
For more information about packet filtering, see, https://go.microsoft.com/fwlink/?LinkId=89010.
Protocols and ports for packet filtering
The following table details some of the common ports and protocols that you might want to allow, depending on your remote access configuration. Not all ports listed here are required for your remote access server. For example, if you are allowing only Layer Two Tunneling Protocol (L2TP), you would not configure a filter for Point-to-Point Tunneling Protocol (PPTP). Similarly, this table might not contain all of the ports that your network needs.
Ports used for protocols
| Protocol | Port | Used For |
|---|---|---|
TCP |
25 |
Simple Mail Transfer Protocol (SMTP) |
TCP |
67 |
Dynamic Host Control Protocol (DHCP) (if the remote access server uses an external DHCP server) |
TCP |
80 |
World Wide Web (HTTP) |
TCP |
110 |
Post Office Protocol, version 3 (POP3) |
TCP |
443 |
SSTP (HTTP over SSL) |
TCP |
1701 |
L2TP |
TCP |
1723 |
PPTP |
TCP |
7250 |
Network Access Quarantine Control (Remote Access Quarantine Client (RQC) messages from client computers) |
UDP |
53 |
Domain Name Service (DNS) (for name resolution of external Web sites) |
UDP |
67 |
DHCP (if the remote access server uses an external DHCP server) |
UDP |
500 |
Internet Protocol security (IPsec) |
UDP |
1701 |
L2TP |
UDP |
1723 |
PPTP |
UDP |
4500 |
IPsec with network address translation (NAT) |
47 |
Generic Routing Encapsulation (GRE) |
|
50 |
Encapsulating Security Payload (ESP) (for firewalls that use NAT traversal [NAT-T]) |
Note
To support Windows Update, you must allow TCP traffic to travel inbound and outbound on port 80 and UDP traffic to travel inbound and outbound on port 53. Depending on your network configuration, you might have to configure these filters on your remote access server, on your firewall, or both.
Static packet filters and Windows Firewall
It is recommended that you enable packet filtering or Windows Firewall, but not both. Conflicts between two sets of filter rules can result in desired traffic being unexpectedly blocked.