Network Documentation Review

Most of our troubleshooting sessions have begun with a quick review of the network documentation. (We look for logical network diagrams showing VLAN's, IP addresses, etc. -- like we would create ourselves with Visio.) In some cases, where no documentation existed, it has been necessary to produce basic network documentation prior to performing actual troubleshooting.

Configuration Review

ITS Networking has resolved many networking issues simply by reviewing firewall configurations, router configurations, and even server NIC addressing and route tables. In several instances, an incorrect firewall access list was blocking allowable outbound traffic. In another situation, a router was missing the required route statements to route packets from the Internet to remote branch sites.

Many other problems can be traced to Microsoft name resolution. ITS Networking Services has resolved many such problems by adjusting DNS or WINS settings.

Network Sniffer

The network sniffer has allowed us to look inside network data streams and "see" what is happening. We routinely use the network sniffer to determine the amount of network broadcast traffic there is on a client network. In some cases we find evidence of protocols that don't belong on the network (IPX, AppleTalk, etc.).

We also use the sniffer to follow specific network conversations. We recently used the sniffer to determine if an application was using unicast or multicast to deliver program files to a group of workstations. We also used the sniffer to see if a new TCP/IP application a client was developing was actually putting any data on the wire.

We have used the sniffer to resolve DHCP issues, name resolution problems, and even identify an ethernet switch that was dropping packets. Experience has proven there is no substitute for a network sniffer when you really need to know what is going on.

To discuss your networking requirements, email us at waltermorris3@yahoo.com OR call (408) 842-8630.

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