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SLUG Pearls #2 For 13 Jun 2000

By Jeff Waugh

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Table Of Contents

Introduction

This week's edition of SLUG Pearls is late because some old dear in a far off country didn't have a birthday, and I was celebrating her unbirthday in that tellingly reverent Australian way: I went to see an action film.

Another blunder: Statistics for this week's SLUG list are sadly unavailable.

This is due to combination of, um, me catting over my mail file (duh!) and the stats software returning some pretty wacky stats. No, our glorious president did not post 1.2MB worth of email this week.

On with the show, eh?

1. Repeaters, Hubs, Blast-off!

4 Jun 2000 - 7 Jun 2000 (27 posts) Archive Link: "repeaters & hubs ##"

People: Minh VanMartin VisserGeorge Vieira

Sometimes it's the simplets of questions that yield the biggest threads on SLUG, and Minh Van sure knows how to start 'em, "what's the difference between a repeater and a hub ? can one be used to do the job of the other ?"

Martin Visser offered this straightforward comparison: " A "hub" is just a repeater with lots of ports. A repeater regenerates the incoming EThernet signal and forwards it out all ports. (This is different from a bridge/switch which makes some smart decisions about which ports to forward traffic on)."

George Vieira added to the desription:

The bonus job of a repeater is also that it can extend the network limit of 100 metres by rebroadcasting the packets onto the other network. Similar to a linux box with 2 network cards and a route between the two.

The drawback is there are alot more chances of getting collisions and the delays are larger due to the retransmission.. but really you don't notice it.

DaZZa responds:

Absolute bollux.

You can extend your network using hubs as well - as long as you apply the 5-4-3 rule to the total segment length and number of repeaters.

DaZZa also explained that the amount of collisions would be similar using either a hub or a repeater. The 5-4-3 rule?

{groans} I knew someone'd ask me that.

It goes something like you can extend your maximum network cable length by extending it across 5 hubs with 4 segments and any 3 of those segments being populated {I.E. having nodes on them}.

Read DaZZa's long post - with diagram - here.

There were various discussions about maximum cable length, availability of networking hardware, and a bit of network engineer one-upmanship, but none quite so scathing as Rodos' comment, " Sheesh, even my 3 year old knows the 5-4-3-2-1 rule, you gotta yell *zero, blast off* at the end!"

2. Proxy Passwords and wget

5 Jun 2000 (8 posts) Archive Link: "wget with proxy authentication"

People: Rick Welykochy

gizmox was looking for a way to wget through an authenticated proxy server, and hadn't found a commandline or .wgetrc option that helped. When Rodos posted a portion of the documentation relating to proxies, gizmox clarified his problem:

Yes, thanks, but...

My username contain the '@' character (I can't change it) and wget responds with invalid port specification or not recognized it at all. How to solve the problem?

Rodos directed gizmox, not to the documentation, man files or web page, but The Source. Whilst gizmox couldn't actually read the source, the problem was solved:

You should therefore be able to use %40 instead of your @ character.

Give http://user%40domain:mypassword@proxy.company.com:8001/

Like the end of a Saturday morning cartoon, Rick chimes in with the moral of the story:

Interesting example of how The Source can solve a seemingly intractable problem.

Compare this to the same problem using a closed product, like a utility from Microslop.

Q: How many phone calls and credit card charges would it take to find out if MS's "wget" utility allows an "@" in the username of a proxy URL?

A: More than you could afford.

3. More Briefcase-Penguin Banter

5 Jun 2000 (7 posts) Archive Link: "Dell + Notebook + Linux - Latest"

People: David SaintyAravind NaiduJeff WaughSimon RumbleMatt Allen

David Sainty gave us an update on his efforts to find a laptop with Linux pre-installed. He was a bit miffed at the lack of a Linux-certified notebook here, whilst there was a model available in the US. A few choice quotes:

"I'm left thinking to myself: 'Oh crap! They're gonna take the Linux notebook into .... the SOUTHERN HEMISPHERE!!! Its gonna blowwwww!!!! <BOOM!!!>'"

"M$ Tax Minimisation: 'The conscious decision to purchase Windoze 98 instead of Windoze NT or Windoze 2000 because less money exits your pocket to M$.'"

"M$ Tax CuT: 'The introduction of a new version of Windoze cheaper than those presently available.'"

Aravind Naidu replied:

When Linux comes pre-installed, they are obliged to answer some questions if say something does not work. It is more like they are dragging their feet getting it up as the perception is that there is not much of a market here. More enquires like this and they will bring it down here.

I long for the day of the 'naked' machine. No OS !!!!

To be sure, Aravind, to be sure. Matt Allen wondered if Dell was receiving money from M$, and if not, whether they'd save money by not installing the Seattle Stifler. Jeff Waugh thought not:

They've got a much bigger bargaining tool: Windows itself.

Can you imagine what would happen if Gateway couldn't sell computers with Windows?

Now you know why they're so shitscared.

Simon Rumble replied, " Well if they refused to sell someone a copy of Windows, they'd get even more hammered by the Justice Dept. However they do have individual and, of course, "commercial in confidence" pricing agreements with each of the vendors. So they could always just start charging them all RRP..."

In other news, Microsoft being hammered by the DOJ.

4. WinModems - The Profit Motive & Hardware

7 Jun 2000 (6 posts) Archive Link: "Rockwell HCF Modem on linux?"

People: Tim Sutton

Tim Sutton wondered whether the great Rockwell HCF PCI modem would work under Linux. Sadly, this particular modem is one of the most frustrating examples of proprietary hardware specifications. The hardware in itself may not be all that bad, but the drivers for it have only ever been written for Windows (thus the monkier WinModems), and the specs have never been released.

This isn't a new thing spurred on by the Microsoft oligarchy: Richard Stallman created the GPL, the Free Software Foundation and countless pieces of software at the heart of our OS... inspired by a printer.

And they tell us not to sweat the small stuff...

5. Warning: Do Not Dig - Network Cables

7 Jun 2000 - 8 Jun 2000 (17 posts) Archive Link: "Home Network"

People: Jamie HonanSimon RumbleJim Clark

Whilst this thread was not specifically Linux-oriented, there were too many good ideas to waste! Jim Clark asked for tips and suggestions for installing network cables and the like in his not-yet completed home.

Simon Rumble suggested conduit instead of cabling, to preempt new kinds of cables coming out to ruin the fun.

Jamie Honan commented that taking photos of cabling before it's covered by gyprock, and installation of draw-wires are useful resources when upgrading. In an attempt to keep the thread on-topic, " ObLinux: (scratches round) Home is so I keep my Linux boxes dry."

David added to Simon and Jamie's ideas, " Talking of concrete slabs... another trick that I have used succesfully is to lay 100mm pvc drainage pipe under the slab, with risers up to the surface at strategic spots around the building. You can cap the risers easily enough. These can be used for running everything from cat5 to front door bells and speaker leads. Draw wires are a good idea, but electrician's eels will do the job if necessary. The last time I did this I ended up with about 15 circuits passing through one pipe. Concrete slabs are very unforgiving if you overlook the need for a particular circuit. "

Various vendors and prices for the components were mentioned.

6. PABX Hell (and Minicom)

9 Jun 2000 (4 posts) Archive Link: "Force Minicom to dial sans dial-tone,"

People:

Peter Rundle was trying to dial out through a PABX that made non-standard noises, confusing Minicom.

DaZZa and Rodos suggested using ATX0, which makes the modem ignore the dial-tone.

7. Apache Virtual Hosts on a Dynamic IP

10 Jun 2000 - 12 Jun 2000 (11 posts) Archive Link: "Virtual hosts on a dynamic IP"

People: Angus Lees

Paul Robinson wanted to know if he could run a number of domains from his dial-up line. His Apache configuration was correct, but he would have to keep changing the ip address in it for the domains to resolve correctly.

ENTERforNone suggested using 127.0.0.1, but noted that it wouldn't be visible to the rest of the 'net, which was a requirement. After various comments, Paul was under the impression that a permanent IP was the only way of making it work.

Angus Lees - who could probably build a nuclear reactor with sed - offered:

nonsense - in your ip-up script (or some dhcp script or something for cable), just put something like this:

myip=$4 # for ip-up, `hostname -i` or something otherwise
sed "s/@MYIP@/$myip/g" < /etc/apache/httpd.conf.orig > /etc/apache/httpd.conf
/etc/init.d/apache/reload

and httpd.conf.orig is just a copy, with @MYIP@ instead of any specific ip address

Which, with a few small changes for Paul's distribution, worked.

 

 

 

 

 

 

Sharon And Joy
 

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