Questions[networking](server)

You know, you see pictures like below and sort of chuckle until you actually have to deal with it.

I have just inherited something that looks like the picture below. The culture of the organization does not tolerate down time very well, yet I have been tasked to 'clean it up'. The network functions as it is, and there doesn't seem to be rush to get it done, but I will have to tackle the bear at some point. I get the ugly eye when I mention anything about weekends.

So my question goes, is there sort of a structured approach to this problem?

My Ideas thus far:

• Label, Label, Label
• Make up my patch cables of desired length ahead of time
• Do each subnet at a time (appears that each subnet are for different physical locations)
• Replace one cable at a time for each subnet
• It's easier to get forgiveness than permision?

I've noticed that the "preferred" method of setting the system hostname is fundamentally different between Red Hat/CentOS and Debian/Ubuntu systems.

CentOS documentation and the RHEL deployment guide say the hostname should be the FQDN:

HOSTNAME=<value>, where <value> should be the Fully Qualified Domain Name (FQDN), such as hostname.example.com, but can be whatever hostname is necessary.

The RHEL install guide is slightly more ambiguous:

Setup prompts you to supply a host name for this computer, either as a fully-qualified domain name (FQDN) in the format hostname.domainname or as a short host name in the format hostname.

The Debian reference says the hostname should not use the FQDN:

3.5.5. The hostname

The kernel maintains the system hostname. The init script in runlevel S which is symlinked to "/etc/init.d/hostname.sh" sets the system hostname at boot time (using the hostname command) to the name stored in "/etc/hostname". This file should contain only the system hostname, not a fully qualified domain name.

I haven't seen any specific recommendations from IBM about which to use, but some software seems to have a preference.

My questions:

• In a heterogeneous environment, is it better to use the vendor recommendation, or choose one and be consistent across all hosts?
• What software have you encountered which is sensitive to whether the hostname is set to the FQDN or short name?

I was wondering if someone could give me a simple guide on how to set up virtual networking in VirtualBox (4.0.2) so that the following scenarios work:

• Both Host and Guest can access the Internet
• Host can ping Guest and vice versa
• Host can access, for example, an apache web server running on Guest and vice versa

I've been fiddling around with the various Network Adapters available in the settings for my Guest, but I'm just not able to figure it out. Is there anyone that can help me out here?

The host is running Windows 7 32-bit and the guest is running Ubuntu 10.10 32-bit.

It's from this answer:

https://stackoverflow.com/questions/2482411/is-this-pdo-bug-fixed-now/2482424#2482424

When the host is "localhost", MySQL Unix clients use a Unix socket, AKA Unix Domain Socket, rather than a TCP/IP socket for the connection, thus the TCP port doesn't matter.

This is a Canonical Question about IPv4 Subnets.

Related:

• How does IPv6 subnetting work and how does it differ from IPv4 subnetting?

How does Subnetting Work, and How do you do it by hand or in your head? Can someone explain both conceptually and with several examples? Server Fault gets lots of subnetting homework questions, so we could use an answer to point them to on Server Fault itself.

• If I have a network, how do I figure out how to split it up?
• If I am given a netmask, how do I know what the network Range is for it?
• Sometimes there is a slash followed by a number, what is that number?
• Sometimes there is a subnet mask, but also a wildcard mask, they seem like the same thing but they are different?
• Someone mentioned something about knowing binary for this?