We have a few Cisco 837's working as L2L's. I have scanned them for vulnerabilities, and received this message, and need jelp to remove it:
ICMP Timestamp Request:
ICMP (Internet Control and Error Message Protocol) is a protocol encapsulated in IP packets. It's principal purpose is to provide a protocol layer able to inform gateways of the inter-connectivity and accessibility of other gateways or hosts. "ping" is a well-known program for determining if a host is up or down. It uses ICMP echo packets. ICMP timestamp packets are used to synchronize clocks between hosts.
Unauthorized users can obtain information about your network by sending ICMP timestamp packets. For example, the internal systems clock should not be disclosed since some internal daemons use this value to calculate ID or sequence numbers (i.e., on SunOS servers).
You can filter ICMP messages of type "Timestamp" and "Timestamp Reply" at the firewall level. Some system administrators choose to filter most types of ICMP messages for various reasons. For example, they may want to protect their internal hosts from ICMP-based Denial Of Service attacks, such as the Ping of Death or Smurf attacks.
However, you should never filter ALL ICMP messages, as some of them ("Don't Fragment", "Destination Unreachable", "Source Quench", etc) are necessary for proper behavior of Operating System TCP/IP stacks.
It may be wiser to contact your network consultants for advice, since this issue impacts your overall network reliability and security.