I left a few things unsaid in my previous post basic hostname set up, and after talking with some people about /etc/hosts, I thought a quick follow up is in order.

Firstly, my preference is to use the ethernet’s ip address to tie the host name to the FQDN, but others like to use 127.0.1.1. There’s a case where you really should use 127.0.1.1 and that’s in laptops where the ethernet interface might disappear when it’s disconnected, probably desktops with dynamic ip addresses, too. But for servers with a static ip address, take your pick, I chose to use eth0.

An example /etc/hosts for a laptop
127.0.0.1 localhost
127.0.1.1 mymailname.com myhostname


Where myhostname is the host name configured in the kernel.

An example /etc/hosts for a server
127.0.0.1 localhost
192.168.1.1 mymailname.com myhostname.mymailname.com someothername myhostname


When the kernel first boots, the host name is configured. How depends on the distribution. Ubuntu seems to use /etc/hostname. In my example /etc/hostname contains myhostname .

When you run the command hostname it does a gethostname() to get the configured host name. It doesn’t reread /etc/hostname every time, it’s stored in the kernel, presumably.

When you want the FQDN, you run hostname -f, it does a gethostname() to get the configured host name, then does a getaddrinfo("myhostname",...) to get the FQDN. Using the last /etc/hosts example, the FQDN is mymailname.com because it’s the first string after the ip address in the line where myhostname appears.

Short names such as the host name myhostname should go at the end of the line, what you want the FQDN to be should be the first string after the ip address, and any other names goes in the middle.

In my examples, I made the FQDN the mail name, because some distributions use the FQDN by default as the mail name. Ubuntu doesn’t, it appears to use /etc/mailname.

Anyway, that’s my understanding based on messing around and reading a man page. Hopefully I’ve explained how the host name and the FQDN is tied together in /etc/hosts.

I was helping out someone with a postfix issue, and something just clicked that will speed up diagnosing similar problems. It’s not so much a postfix problem as a hostname problem, and it’s very basic.

The symptom was, mail sent to the server at domain.com was being bounced. Looking at postfix logs, postfix was trying to deliver the mail to s123.s123. (something like that, anyway)

To the quick, hostname printed s123 and hostname -f said something to the tune of it couldn’t find the FQDN.

The fix, edit /etc/hosts to look like


127.0.0.1 localhost
1.2.3.4 domain.com s123


Where 1.2.3.4 is the ethernet’s ip address.

Now, hostname said s123 and hostname -f said domain.com . A restart of postfix, and it was accepting mail again.

The thing that clicked was the relationship between /etc/hosts, hostname and hostname -f.

See basic hostname set up part 2

I’ve being walking down to The Georges River lately for exercise, and there’s a nice looking bike/walk path where I sit down to rest. So I decided to head down there on my bike and check it out.

My first ride in years, my tyres are flat, bike computer battery is flat, half a bottle full of water left in the cage. After doing a bit of maintenance, including swapping out the one metal water bottle cage for a matched pair of plastic cages with aluminium bottles, I set off.

As I ride, I’m repeating in my head “remember my feet are clicked in” “remember my feet are clicked in”. It’s not uncommon when you’re not used to riding with clipless pedals to fall over when you stop. embarrassing. I didn’t fall over, this time.

I got to the bike path and turned left, it winds along the river, in between trees, and stops 50 metres ahead. OK, looks like left isn’t the right direction. I turn around, head back to where I started and continue on. It ends 20 metres down the track. Not exactly a long bike path.

Since this is the first ride in ages, and I’m not trying to break any long distance records, I decide to head home. In the end, it was the perfect length ride. I’m puffed, coughing a little, and walking up my stairs is a real trial, my quads are dead.

Aside from the general want to get back into fitness, this inspired me to get back on the bike. Cycling The Americas

Now I’m back on the bike, I need to fit it out Geek My Ride, style, with Linux and GPS.

I just read a post I wanted leave a comment on, but it didn’t allow comments, so I will jot my thoughts down here.

You’ve just spent the last 10 minutes searching for an answer to a problem you’ve got, maybe you had the same problem a few years ago and forgot the answer. You find the answer in a search engine with some obscure search term buried on page 9. You want to blog about it and link to the post, 1, for your own future reference so you can find the info easily in a few years time if the problem reoccurs, and 2, you want to boost the profile of the page to help other people find the same info.

Don’t anchor the link as: here’s some info found on “Joe’s blog” on hoophen frangers, anchor the link as: here’s some info found on Joe’s blog on “hoophen frangers”. ie, put the topic in the anchor, not the blog owners name.

Both ways send “juice” to the page, but the second way associates the topic to the page, rather than the authors name. The first way will help when people search for authors name, the second way will help when people search for the topic.

If you want, make two links, anchor the authors name to the front page or the about page of the blog, and anchor the topic to the blog post’s permalink.

For a while now, I had not being using FreeSWITCH for my VoIP, but just logging into PennyTel directly with my Nokia E65. It worked OK, but the voice quality wasn’t as good as going through FreeSWITCH.

A month ago my old ADSL router died, so I bought a Billion 5200N to replace it. Since then, I’d been having weird problems with VoIP not working, and the Wifi to LAN bridging stopping dead whenever there was a bit of traffic over it.

It took me a while to sort out all the peculiarities of the Billion.

1. A change of ethernet ports on the router fixed the bridge locking up problem. It took a lot of time and weird theories before I fixed that.
2. When setting up the router from factory defaults, I have to save the wireless interface twice when I change the SSID before it will allow my wireless devices to authenticate.
3. UPnP was interfering with FreeSWITCH, and probably my Nokia. Turning that off on the router fixed FreeSWITCH.
4. Selecting some settings on the router made the routers wireless interface disappear, and the only way to get it back was a factory reset.

So, FreeSWITCH is a breeze to set up for PennyTel now. It takes editing two files.
conf/vars.xml and conf/dialplan/default/000pennytel.xml.

In conf/vars.xml I changed the following

<X-PRE-PROCESS cmd="set" data="default_password=whateveryouwant"/>

That password is used for phones authenticating to FreeSWITCH, it has nothing to do with PennyTel.


<X-PRE-PROCESS cmd="set" data="domain=switch.gruntnet"/>


What the phones use as their realm, it should be in the DNS with the ip pointing to FreeSWITCH.


<X-PRE-PROCESS cmd="set" data="default_provider=sip.pennytel.com"/>
<X-PRE-PROCESS cmd="set" data="default_provider_username=61281955555"/>
<X-PRE-PROCESS cmd="set" data="default_provider_password=55555/>
<X-PRE-PROCESS cmd="set" data="default_provider_from_domain=sip.pennytel.com"/>
<!-- true or false -->
<X-PRE-PROCESS cmd="set" data="default_provider_register=true"/>
<X-PRE-PROCESS cmd="set" data="default_provider_contact=1000"/>


All the PennyTel setting goes above, I use 1000 to receive incoming calls, my only phone on the network.

Then in conf/dialplan/default/000penntel.xml


<extension name="pennytel">
<condition field="destination_number" expression="^(.*)$">
<action application="set" data="effective_caller_id_number=61281955555"/>
<action application="bridge" data="sofia/gateway/sip.pennytel.com/$1"/>
</condition>
</extension>


I recently upgraded to snow leopard and noticed some DNS weirdness. I couldn’t ssh to hosts defined in my local DNS, it wouldn’t resolve, but I could resolve them with the host command.

Turns out Snow Leopard made quite a few changes to the resolver, it no longer uses /etc/resolv.conf but mDNSResponder, at least for apple supplied applications.

Unlike every other OS I’ve come across, including Leopard, Snow Leopard doesn’t use the order of DNS servers as first listed, first used. It swaps which DNS it’s going to use around, seemingly at random times. Some sort of load balancing miss feature?

I had two DNS servers configured, the first one, my local DNS server, the second, my ADSLs DNS server as a backup. The simple fix is to only have one DNS server configured.

There’s more information here Snow Leopard Resolver.

I’m not unhappy with OS X, but lately I’ve been pining to return to a linux based laptop. I think this will be my first and last Mac.

I had a job come in last week for a linux file server to connect a few windows machines together, and a few printers. The client was exposed to a linux file server in a previous job, and wanted something similar.

It was a small business, with not much money to spend, and the server was to be located in the office, no server room. This is the type of job I love doing.

I sourced an ex corporate desktop for about $150 including shipping, I think they can be had for a little less, but this was convenient. It was a P4 with SATA, which is what I was looking for. The ugliest case you could image, but had space for two hard drives. DVD writeable drive, 1 gig memory, built in gigabyte ethernet. It was perfect.

I bought two new 500 gig green SATA drives for RAID 1 configuration, $70 each, and an external 500 gig drive for backup, which ran $100. So about $400 in hardware, but a really nice set up, should be very reliable, and the data should be very safe.

I was a bit of a cowboy when it came to the operating system, with karmic about to be released, I chose it over jaunty or LTS because it had a newer Samba. Turns out the Samba version wasn’t very important as most of the PC’s were running XP home edition, which doesn’t even do domain logins.

I tired to convince the client to get two external drives to keep one off site in case of a fire or something. But instead we are using the DVD drive to write backups for off site storage.

It was a really nice job, gave me a lot of energy and the client is happy. Can’t ask for more than that.

I wanted a few programming projects to do to keep juices flowing. I came up with two twitter ones, http://twitter.com/slugupdates and http://twitter.com/cityrailupdates. Inspired by Lindsay’s bushfire project.

They are both little python programmes.

slugupdates just waits for messages posted to the slug announce list, procmail carbon copies the message and pipes it to the programme, the programme uses the subject as the tweet message.

cityrailupdates scrapes the major delays announcement page and tweets the time and title. It uses python’s beautifulsoup to do the scraping.

Both projects were fun and satisfying. I’ve still got some work to do with cityrailupdates, I want to save the whole message in a database and have a little front end to it for historical data.

Barrang officially opens its doors on the 19th of February, 2009.

Barrang is starting out primarily as a Linux Consultancy mainly targeting local small businesses in south west Sydney.

My primary target market doesn’t have a lot of money, especially in this climate, so I intend to provide maximum value to my clients by using Open Source Software as much as possible and by keeping my rates as low as possible.

My long term goal is to be location independent, that means not being tied to servers located in customer premises. There’s a number of different paths that goal could take, and I will be developing them along the way as I go.

My strengths lie in my knowledge and experience in Open Source Software and networks. My weakness is in social networking and marketing. So if you would like to reach out and make contact, please do, I welcome and encourage it.

There’s no launch party, this post is the cutting of the ribbon.

I look forward to getting to know you more, working together, and making a living doing what I love.

I’ve been searching for accounting packages lately for my IT business which is officially launching tomorrow (yay me), but has sort of been running for the last few years.

My dad is an accountant, and is a wiz at MYOB. So I thought I may as well give it a go, somewhat reluctantly. I couldn’t get it to work properly in my windows VM. Text would disappear from an invoice, and the dates were in US format, even though windows was set to AU. I put it in the too hard basket, and looked at FOSS alternatives.

First stop, LedgerSMB. It was quite alien to me and took a bit to get used to, mostly because I’m not that familiar with accounting practices.

It worked well enough, and I got used to it, however, after recording on an invoice that it had been paid, I got a duplicate key error, and the invoice disappeared. I couldn’t find it in any of the reports, and digging into the backend, I couldn’t see any trace of it in the database. So I dumped it.

Next was Fivedash, which I had never heard of, but was mentioned on OpenSSG. First impressions was it’s very slick, and basic compared to LedgerSMB. But it has all the functionality I need, and has a CRM built in too.

It’s still in beta, and the community isn’t that big. But so far it’s working well, and based on what I’ve read, it can be trusted a lot more than LedgerSMB, in which I get the impression has many warts.