As mentioned previously on my previous thread about SharePoint 2010 ports, there will be times that you would need to test ports on SharePoint 2010 or ports that SharePoint needs to receive incoming / out coming connections. The following Windows TCP / IP utilities will help answer a lot of these issues
Ping
Ping is a computer network administration utility used to test the reachability of a host on an Internet Protocol (IP) network and to measure the round-trip time for messages sent from the originating host to a destination computer. So assuming you were using Windows Server 2008 or Windows 7, and you wanted to check that a client computer was contacting its local domain controller, assuming the IP address of the server or domain controller was 10.0.0.1, from the client machine you would Click on Start > All Programs > type CMD
Type Ping 10.0.0.1 and press enter
After a few minutes, you would then have a series of replies including the packets sent and received. If there is 0% loss, then it means that there is connectivity between both servers.
Sometimes, you may have the message saying Timed Out. This is either due to firewall restrictions, or other connectivity issues, or really an indication that there is no connectivity between both servers.
Other Ping Commands:
ping 127.0.0.1 – This can be used to check that your windows service is truly functional on a network and that all Windows network functions are configured correctly, especially web aspects.
ping -a (**ip address**) Here the ping command will find(resolve to) the hostname assigned to an ip address. So using ping -a 10.0.0.1 in the previous example will display the host name of a domain controller.
ipconfig
ipconfig (internet protocol configuration) will display all current TCP/IP network configuration values. By typing ipconfig /all. All details of the current TCP/IP connections will be displayed.
netstat
netstat (network statistics) displays network connections (both incoming and outgoing), routing tables, network interfaces and network protocol statistics from a client / server computer and can be used for finding problems in the network and to determine the amount of traffic on the network as a performance measurement.
Other netstat commands include
netstat -a which will provide a list of all available TCP and UDP connections,
netstat -e which will display details of packets that have been sent
netstat -n which will list currently connected hosts
netstat –f Which will displays fully qualified domain names <FQDN> for foreign addresses (only available on Windows Vista and newer operating systems).
netstat –r Displays the contents of the IP routing table.
netstat – b –v This will display the sequence of components involved in creating the connection or listening port for all executables.
nslookup
nslookup can be used for querying DNS (Domain Name System) to obtain domain name or IP address mapping or for any other specific DNS record.
tracert
i.e. traceroute displays the route (path) and also measures transit delays of packets across an Internet Protocol (IP) network. In other words, it checks connectivity from one computer to another it gives you the details of the hops it goes through
Telnet
Telnet is a client-server protocol, based on a reliable connection-oriented transport. Typically this protocol is used to establish a connection to Transmission Control Protocol (TCP) port number 23, where a Telnet server application (telnetd) is listening.However, it can be used to test listening on other ports. Telnet Client is not installed by default on Windows 7, Windows Server 2008 R2, Windows Vista, or Windows Server 2008. The procedures to install Telnet Client vary based on the operating system you are using but can be easily done using the Command tool and falling the following steps
-Ensure you right click as an administrator
-Open a command prompt window. Click Start, type cmd in the Start Search box, and then press ENTER.
-Type the following command: pkgmgr /iu:"TelnetClient"
-If the User Account Control dialog box appears, confirm that the action it displays is what you want, and then click Continue.
-When the command prompt appears again, the installation is complete.
To run Telnet commands, from the command tool
Telnet **ipaddress** -the IP address of the client **Port Number**-the port number that it is meant to communicating with on outbound.
if the port is opened, you will see a blank screen in command prompt....
There are many other tools and commands, but for SharePoint, these are the ones that I have found to really help in resolving a lot of connectivity issues that I have experienced while managing and architecturing SharePoint sites and applications.