above. However, if you have nnmaster running as daemon, you must kill it (using
# nnmaster -kF ''
# nnmaster -lrC
There are many more flags that fine-tune the nn 's behavior. If you are concerned about removing bad articles or assembling article digests, read the nnmaster manual page.
nnmaster relies on a file named
Appendix A. Example Network: The Virtual Brewery
Throughout this book we've used the following example that is a little less complex than Groucho Marx University and may be closer to the tasks you will actually encounter.
The Virtual Brewery is a small company that brews, as the name suggests, virtual beer. To manage their business more efficiently, the virtual brewers want to network their computers, which all happen to be PCs running the brightest and shiniest production Linux kernel. Figure A.1 shows the network configuration.
On the same floor, just across the hall, there's the Virtual Winery, which works closely with the brewery. The vintners run an Ethernet of their own. Quite naturally, the two companies want to link their networks once they are operational. As a first step, they want to set up a gateway host that forwards datagrams between the two subnets. Later, they also want to have a UUCP link to the outside world, through which they exchange mail and news. In the long run, they also want to set up PPP connections to connect to offsite locations and to the Internet.
The Virtual Brewery and the Virtual Winery each have a class C subnet of the Brewery's class B network, and gateway to each other via the host
Figure A.1: The Virtual Brewery and Virtual Winery subnets
Figure A.2: The Virtual Brewery Network
Connecting the Virtual Subsidiary Network
The Virtual Brewery grows and opens a branch in another city. The subsidiary runs an Ethernet of its own using the IP network number
Appendix B. Useful Cable Configurations
If you wish to connect two computers together and you don't have an Ethernet network, you will need either a serial null modem cable, or a PLIP parallel cable.
These cables can be bought off the shelf, but are much cheaper and fairly simple to make yourself.
A PLIP Parallel Cable
To make a parallel cable to use for PLIP, you will need two 25-pin connectors (called DB-25) and a cable with at least eleven conductors. The cable must not be any longer than 15 meters (50 feet). The cable may or may not have a shield, but if you are building a long cable, it is probably a good idea to have one.
If you look at the connector, you should be able to read tiny numbers at the base of each pin - from 1 for the pin at the top left (if you hold the broader side up) to 25 for the pin at the bottom right. For the null printer cable, you have to connect the following pins of both connectors with each other, as shown in Figure B.1.
All remaining pins remain unconnected. If the cable is shielded, the shield should be connected to the DB- 25's metallic shell on just
A Serial NULL Modem Cable
A serial null modem cable will work for both SLIP and PPP. Again, you will need two DB-25 connectors. This time your cable requires only eight conductors.
You may have seen other NULL modem cable designs, but this one allows you to use hardware flow control - which is far superior to XON/XOFF flow control - or none at all. The conductor configuration is shown in Figure B.2:
Again, if you have a shield, you should connect it to the first pin at one end only.
Figure B.1: Parallel PLIP cable
Figure B.2: Serial NULL-Modem cable
Appendix C. Copyright Information
Copyright © 1993 Olaf Kirch Copyright © 2000 Terry Dawson Copyright on O'Reilly printed version © 2000 O'Reilly& Associates
The online version of this book, which at this time of printing contains exactly the same text as the O'Reilly printed version, is available under the GNU FDL. Rights to reprint the document under the FDL include the right to print and distribute printed copies of the online version. Rights to copy the O'Reilly printed version are reserved.
