I found a hiddem gem the other day from Microsoft that is designed for testing ports: Portqry.exe “Portqry.exe is a command-line utility that you can use to help troubleshoot TCP/IP connectivity issues. Portqry.exe runs on Windows 2000-based computers, on Windows XP-based computers, and on Windows Server 2003-based computers. The utility reports the port status of … Read more
Note: This message is a symptom of the problem you are trying to solve. Understanding the cause of the message will ultimately lead you to solving your problem. The message ‘Connection Refused’ has two main causes: Nothing is listening on the IP:Port you are trying to connect to. The port is blocked by a firewall. … Read more
Virtual LANs (VLANs) are an abstraction to permit a single physical network to emulate the functionality of multiple parallel physical networks. This is handy because there may be situations where you need the functionality of multiple parallel physical networks but you’d rather not spend the money on buying parallel hardware. I’ll be speaking about Ethernet … Read more
Try this: Setup the virtualbox to use 2 adapters: The first adapter is set to NAT (that will give you the internet connection). The second adapter is set to host only. Start the virtual machine and assign a static IP for the second adapter in Ubuntu (for instance 192.168.56.56). The host Windows will have 192.168.56.1 … Read more
The command you are looking for is called nslookup, works fine for reverse lookups IFF someone has configured a reverse zone file, which they don’t always do.
The MAC address might be unique, but there’s nothing special about the number that would indicate where it is. MAC 00-00-00-00-00-00 might be on the other side of the planet from 00-00-00-00-00-01. IP is an arbitrary numbering scheme imposed in a hierarchical fashion on a group of computers to logically distinguish them as a group … Read more
Quoting Thomas Pircher‘s website (cc-by-sa): ifconfig vs ip The command /bin/ip has been around for some time now. But people continue using the older command /sbin/ifconfig. Let’s be clear: ifconfig will not quickly go away, but its newer version, ip, is more powerful and will eventually replace it. The man page of ip may look … Read more
I would choose a consistent approach across the entire environment. Both solutions work fine and will remain compatible with most applications. There is a difference in manageability, though. I go with the short name as the HOSTNAME setting, and set the FQDN as the first column in /etc/hosts for the server’s IP, followed by the … Read more
A UNIX socket, AKA Unix Domain Socket, is an inter-process communication mechanism that allows bidirectional data exchange between processes running on the same machine. IP sockets (especially TCP/IP sockets) are a mechanism allowing communication between processes over the network. In some cases, you can use TCP/IP sockets to talk with processes running on the same … Read more
In no particular order here are some suggestions that have been helpful to me over the years- Can any of the equipment in those racks be eliminated, upgraded or consolidated? It’s hard to tell what’s there, but in my experience these kinds of messes tend to be aggravated by gear that should have been pulled … Read more