JDPFu.com 2025

Below is the 5th of 6 questions from a reader. I definitely don’t have all the answers, but I’m not short on opinions. ;)

Previous articles:
Part 1 – LVM+JFS+RAID | Part 2 – Service Virtualization |
Part 3 – Virtualizing Media Storage | Part 4 – Hosting Email

duijf asks:

Q5: Do I need a reverse proxy if I ? I’ve read about proxy servers on TheFu’s blog that filter internal traffic (if you read this, in the end I liked the idea a lot more than at first). Is this even the same thing? If this is to happen, is it correct that I’d need two NICs and bridge the connection from the router to the internal network? If so, can I get rid of the router? We do use it for telephone access too.

Below is the 2nd of 6 questions from a reader. I definitely don’t have all the answers, but I’m not short on opinion. ;)

Part 1 – LVM+JFS+RAID | Part 2 – Service Virtualization | Part 3 – Virtualizing Media Storage | Part 4 – Hosting Email

duijf asks:

Q2: I read everywhere about Virtualisation, should I directly install packages to the base system to provide services, or should I virtualise all services? What are the advantages here?

Advantages of Virtualization

The list of advantages is long, but with those advantages comes a few disadvantages. I cannot hope to point out all the advantages, so I’ll limit it to just the main ones.

Sometime on Monday the database that we run our blog software on became corrupted to the point that accessing the blog wasn’t possible for hours, perhaps many, many hours.

I don’t know how long the error existed, just that I created a few new articles in the morning and didn’t check back until late afternoon to see the process eating 99.99% of the available CPU AND not serving any pages.

Below is the first of 6 questions from a reader. I definitely don’t have all the answers, but I’m not short on opinion. ;)

Part 1 – LVM+JFS+RAID | Part 2 – Service Virtualization | Part 3 – Virtualizing Media Storage | Part 4 – Hosting Email

duijf asks:

I have a total of 5 quiet 5400RPM 1TB drives configured in a RAID5+1 array. I installed Ubuntu Server 10.04 onto LVM , inside the LVs JFS is used as the file-system. Is this good practice?

I have used Thunderbird for at least 8 yrs and used Mozilla Mail built into Mozilla/Netscape before that. When the company started using Zimbra for email, IM, calendaring, Lightning never quite worked correctly. With v5 of Thunderbird, the integration to Zimbra with Lightning is working well. After using it about 2 months, I haven’t seen any failures – even on complex calendar settings.

Thunderbird v5 + Lightning Installation Steps

These instructions are for Ubuntu, but probably work with other distros too.

sudo add-apt-repository ppa:mozillateam/thunderbird-stable
sudo apt-get update
sudo apt-get install thunderbird  xul-ext-lightning

Sometimes I lose track of all the devices on a network and need a reminder of everything that is there. Under IPv6, you won’t scan the entire subnet – it would take millions of years – but under IPv4, you still use a scan. nmap is good for this and running it with operating system finger printing goes quickly (relatively speaking).

nmap OS finger print command

$ sudo nmap -O 192.168.0.0/24

Bare with me here. This is a great technique. I think you’ll thank me later after doing what this article suggests.

Homes and businesses today have lots of network devices. Using DHCP is the easiest way to get those on the network, but if you ever want those different devices to talk to each other, perhaps to transfer a file or to have a central backup server, then now your are running a network. Running a network means you probably want to know which devices are on your network or maybe that is just me. Perhaps you want each device to locate each other device too? Static IPs are possible under DHCP, sometimes called DHCP Reservations or Static Leases.

Make it easy for everyone in the house by using your router to force static IPs for the devices when they are at home, but still can connect to DHCP networks easily when roaming. This is really good for portable WiFi devices like laptops, smartphones, and for home entertainment devices that easily support DHCP.

Linux/Ubuntu (maybe others) – ssh key-based authentication made easier.

You know that you shouldn’t be using passwords to remotely connect to a different machine, but setting up key-based authentication has always been just a little too much hassle to bother. It really is simple, but there’s a tool to make it even easier. ssh-copy-id is included with Ubuntu-based distros (and probably others) to push the public key from your desktop to a server and append that public key to the end of the ~/.ssh/authorized_keys file.

FTP, File Transfer Protocol, has been around since the beginning of the internet in the early 1970s. It transfered files when the internet was a safer, more trusting, place. That isn’t the case anymore. Using FTP to host files is probably a bad idea for almost everyone. FTP is like Telnet. No encryption is used for anything. These days, we know that is bad.

In the mid-1990s most organizations stopped using telnet and switched to ssh, secure shell. FTP needs to be replaced for the same reasons. Below I’ll describe why very few people should use plain FTP anymore to remotely access files.

About a month ago, an editor at a large blog website followed one of my links in a comment there back here and offered to republish the story. I was already seeing increased traffic from that link on their site – like 10x more than my normal daily traffic – and it scared me. I don’t have the bandwidth to handle that sort of traffic and my Ruby on Rails blog software … er … pretty much sucks from a scalability perspective. What did I do?