With filters on your Routing and Remote Access Service (RRAS) server
configured to allow your network to ping remote hosts and to disallow the
remote hosts from pinging your RRAS server or internal network hosts, you
may notice that ping does not work in either direction.
When setting the input ICMP filter, the ICMP type and ICMP code fields are
blank. This causes the default type and code value of 255 to be used. When
255 is used, all ICMP packets will be blocked (not received), including
type 0, which is Echo Reply. When your computer tries to ping a host, the
host replies with an Echo Reply ICMP packet, but because of the filter, the
packet is discarded.
To resolve this issue set up the filters using the following steps:
- Click Start, point to Programs, point to Administrative Tools, and
then click Routing and RAS Admin.
- Double-click IP Routing, click Summary, and then right-click the
interface on which you want to configure filters.
- Click Configure Interface, click Input Filters, and then click Add.
- In the Protocol drop-down list, select ICMP and type 8 in the ICMP type
NOTE: Type 8 denotes an Echo Request.
- Click OK and click Receive all except listed below.
- Click OK in the IP Packet Filters Configuration dialog box.
- Click OK in the IP Configuration dialog box for the specific interface.
For more information, please see the following article in the Microsoft
TITLE : Internet Control Message Protocol (ICMP) Basics