Extended ACLs are advanced than the Standard ACLs. Unlike the Standard Access Lists where it checks only the Source IP Address to control the flow of the packets, Extended ACLs can check the
Source & Destination Address
Protocols (IP,ICMP,TCP,UDP)
Source & Destination ports
One of the most important thing that is ignored most of the time while troubleshooting a network problem to a host or a network is checking the MTU related issue. This makes more sense in situations like troubleshooting VPN related issues.
MTUROUTE is a small but smart utility that uses ICMP pings of various sizes in order to determine the MTU values (Maximum Transmission Unit) on the path between itself and the target system. MTUROUTE can operate in normal mode where it sends multiple ICMP packets to each hop on the path to identify the smallest MTU between the host and hop or in a Traceroute mode where it will attempt to determine the lowest MTU between the local host and each hop in the communication.
It is important to note that care has to be taken as it generates muti fold ICMP traffic as it tries to determine the MTU Values.
ARPing is an utility that can be used to ping using ARP requests instead of using ICMP as used in standard Ping utility.
Because it involves ARP, arping is limited to the local network to which the server or the interface (if more than one interface) is connected to. ARPing can be quite useful to
fping is a ping like program which uses the Internet Control Message Protocol (ICMP) echo request to determine if a host is up. fping is different from ping in that you can specify any number of hosts on the command line, or specify a file containing the lists of hosts to ping.
Windows XP Professional, Windows 2003 and Windows 2000 supports TCP/IP filtering. TCP/IP filtering allows you to specify exactly which types of incoming IP traffic are processed as the destination for each IP interface. This feature is designed to isolate the traffic being processed by Internet and intranet clients in the absence of other TCP/IP filtering provided by IPSec, the Routing and Remote Access service, or other TCP/IP applications or services. TCP/IP filtering is disabled by default. (more…)