Early experiments in building gateways

Last Updated on April 17, 2017 by Dave Farquhar

Gateways. I worked with Gatermann last night after I got back from church (three Macs and an NT server died yesterday–I needed it last night) on trying to get his Linux gateway running under FloppyFW . We were finally able to get it working with dual NICs, able to ping both inside and outside his LAN (I finally found an old Pentium-75 board that didn’t have compatibility issues). But we weren’t able to actually get his Web browsers working.

I suspect something about the IP masquerading configuration just isn’t right, but it’s been so long since I wrote one of those by hand (and it was really just copycating an existing configuration), so since I have working Linux boxes at home I finally just gave up and downloaded the shell script version of Coyote Linux and ran it. It’s not foolproof because you have to know what kernel module your Ethernet cards use, but assuming you know that (make it easy on yourself–get a pair of Netgear 10/100 cards, which use the Tulip module), but it’s definitely a two-edged sword. It makes it a little harder to configure, but it means it’ll work with a much wider variety of cards. If Linux supports it, so does Coyote, whereas a lot of the other single-floppy distributions just support the three most common types (NE2000, 3Com 3c509, and DEC Tulip). So an old DEC Etherworks3 card will work just fine with Coyote, while getting it to work with some of the others can be a challenge.

I’m disappointed that Coyote doesn’t include the option to act as a caching DNS, because you can fit caching DNS on the disk, and it’s based on the Linux Router Project, for which a BIND tarball is certainly available. I’ll have to figure out how to add BIND in and document that, because there’s nothing cooler than a caching nameserver.

I was messing around briefly with PicoBSD , a microdistribution of FreeBSD, but the configuration is just different enough that I wasn’t comfortable with it. FreeBSD would be ideal for applications like this though, because its networking is slightly faster than Linux. But either Linux or FreeBSD will outperform Windows ICS by a wide margin, and the system requirements are far lower–a 386, 8 megs of RAM, floppy drive, and two NICs. Can’t beat that.

Rarely used trivia department: Using Linux to create disk images. To create an image of a floppy under Unix, use this command: dd if=/dev/fd0 of=filename.img bs=10k . There’s no reason why this command couldn’t also be used to clone other disks, making a single-floppy Linux or FreeBSD distribution an alternative to DriveImage or Ghost, so long as the disks you’re cloning have the same geometry.

Test this before you rely on it, but the command to clone disk-to-disk should be dd if=/dev/hda of=/dev/hdb while the command to clone disk-to-image should be dd if=/dev/hda of=filename.img and image-to-disk should be dd if=filename.img of=/dev/hda .

And yesterday. While the computers (and I’ll use that phrase loosely when referring to those Macs) were going down all around me at work, the mail was pouring in. Needless to say, some people agree and others don’t. We’ll revisit it tomorrow. I’ve gotta go to work.

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