June 2006 - WLUG - wlug.mailman3.com

SoC's with USB host

by Jamie Guinan

To follow up on discussion about USB capabilities, I took a quick look at which platforms support USB host (so you can plug webcams, etc. *into* it), $ cd linux-2.6.16 $ find . | grep ohci ... ./drivers/usb/host/ohci-s3c2410.c [ Samsung ARM 920T ] ./drivers/usb/host/ohci-sa1111.c [ StrongARM(SA1110) companion Chip ] ./drivers/usb/host/ohci-lh7a404.c [ Sharp ARM920T ] ./drivers/usb/host/ohci-ppc-soc.c [ Various PowerPC (Freescale) ] ./drivers/usb/host/ohci-au1xxx.c [ AMD (formerly Alchemy) MIPS Au1000 ] ./drivers/usb/host/ohci-pxa27x.c [ XScale ARM (successor to SA1110] ... Those modules are thin hardware-specific glue around the main ohci/usb kernel code. I think the gumstix is a pxa25x, and only the 27x supports USB host. Development boards for a lot of these are priced rather high for the typical hobbyist budget, from a few hundred $$ on up, http://www.embeddedplanet.com/products/sbc.asp http://dkc3.digikey.com/PDF/T062/0378.pdf http://www.hitechglobal.com/boards/ARM920T.htm It looks like Gumstix and routerboard are the cheapest available products in this class. And they're great, but hopefully in the we'll see more things aimed at hobbyists, with USB host capability. -Jamie

June 9, 2006

Re: [Wlug] Problem with usermod

by Adam Keck

Hello Chuck, Another thing you can do is to pass init=/bin/bash to the kernel via grub at boot time. / will be mounted ro; remount it and /tmp rw and then edit /etc/group (vi /etc/group, vigroup (sp?), or use usermod by mounting /usr as well). This is why it is a good idea to use grub passwords on public machines ;-). -Adam On May 10, 2006, at 10:24 AM, Chuck Noyes wrote: > Hi All, > > I'm running ubuntu (brezzy), and I just shot myself in the foot.... > > I went to add my username to a new group, but forgot to include the > other groups that I belong to in the command. The command I used was > 'sudo usermod -G <new-group> <my-username>'. Now I only belong to > <new-group>. That removed my username from the other groups I belonged > to, including the admin group. > > Is there a way undo what I did? I do have a copy of /etc/group before > the change. > > Thanks, > -Chuck > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org > http://mail.wlug.org/mailman/listinfo/wlug

June 4, 2006

Re: [Wlug] dhcpd question

by Eric Martin

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Thanks for the pointers on that, I will incorporate those changes. About that comment, I re-read the config file and I see exactly what you're talking about, I just forgot to delete the comment before I emailed this off originally. Chuck Anderson wrote: > On Sat, Jun 03, 2006 at 07:11:24AM -0400, Eric Martin wrote: >> # Everybody in here will not get an ip whatsoever pool { range >> 10.10.20.20 10.10.20.127; deny known-clients; host slide { >> hardware ethernet 00:c0:9f:15:d7:3f; } } pool { range >> 10.10.20.128 10.10.20.253; deny unknown-clients; host fixed { >> hardware ethernet 00:11:22:33:44:55; # >> fixed-address 10.10.20.25; } } } > > You've made several of the classic mistakes that everyone makes at > first when learning ISC dhcpd (including myself :-) ). > > host {} blocks are always global in scope, regardless of where in > the configuration they are placed. Putting them inside pool {} > blocks just confuses readers into thinking they are locally scoped. > So, in this configuration both hosts "slide" and "fixed" are > considered known-clients, and they will both get dynamic addresses > out of the second pool unless the fixed-address was uncommented for > host "fixed" in which case "deny known-clients" etc. doesn't apply > at all (they only apply to dynamic assignments). > > Another thing: fixed-address assignments must not be inside of pool > ranges. The server will not check for such conflicts of > static/dynamic addressing, so you will get duplicate IP assignments > to more than one client in case fixed-addresses and ranges overlap. > You can exclude the fixed-addresses like this: > > pool { range 10.10.20.20 10.10.20.24; range 10.10.20.26 > 10.10.20.127; [....] } > > Common practice is to not intersperse fixed-addresses throughout > multiple pool ranges, to prevent unwieldy configurations with > multiple range statements per pool. Rather, fixed-addresses are > usually assigned contiguously together outside of a single pool > range. > > Finally, when you say "everybody in here will not get an ip > whatsoever", that is not true. The "deny known-clients" > implicitely does "allow unknown-clients", and vice versa, so > unknown-clients (those without any matching host {} declaration) > will get dynamic addresses out of the first pool. > _______________________________________________ Wlug mailing list > Wlug(a)mail.wlug.org http://mail.wlug.org/mailman/listinfo/wlug > -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.2 (GNU/Linux) iD8DBQFEgcPUaI8VEtSi4H8RAi7mAKCJ1C8E2FH4zJSItxUaBNukbs0o5ACfQW20 qUoOtQqOyIBa+iy+upTbTkg= =f9/t -----END PGP SIGNATURE-----

June 3, 2006

Re: [Wlug] dhcpd question

by Chuck Anderson

On Sat, Jun 03, 2006 at 07:11:24AM -0400, Eric Martin wrote: > # Everybody in here will not get an ip whatsoever > pool { > range 10.10.20.20 10.10.20.127; > deny known-clients; > host slide { > hardware ethernet 00:c0:9f:15:d7:3f; > } > } > pool { > range 10.10.20.128 10.10.20.253; > deny unknown-clients; > host fixed { > hardware ethernet 00:11:22:33:44:55; > # fixed-address 10.10.20.25; > } > } > } You've made several of the classic mistakes that everyone makes at first when learning ISC dhcpd (including myself :-) ). host {} blocks are always global in scope, regardless of where in the configuration they are placed. Putting them inside pool {} blocks just confuses readers into thinking they are locally scoped. So, in this configuration both hosts "slide" and "fixed" are considered known-clients, and they will both get dynamic addresses out of the second pool unless the fixed-address was uncommented for host "fixed" in which case "deny known-clients" etc. doesn't apply at all (they only apply to dynamic assignments). Another thing: fixed-address assignments must not be inside of pool ranges. The server will not check for such conflicts of static/dynamic addressing, so you will get duplicate IP assignments to more than one client in case fixed-addresses and ranges overlap. You can exclude the fixed-addresses like this: pool { range 10.10.20.20 10.10.20.24; range 10.10.20.26 10.10.20.127; [....] } Common practice is to not intersperse fixed-addresses throughout multiple pool ranges, to prevent unwieldy configurations with multiple range statements per pool. Rather, fixed-addresses are usually assigned contiguously together outside of a single pool range. Finally, when you say "everybody in here will not get an ip whatsoever", that is not true. The "deny known-clients" implicitely does "allow unknown-clients", and vice versa, so unknown-clients (those without any matching host {} declaration) will get dynamic addresses out of the first pool.

June 3, 2006

Re: [Wlug] dhcpd question

by Bill Smith

On Sat, 2006-06-03 at 07:11 -0400, Eric Martin wrote: > Basically what you want is at least two pools. The first pool will do > the most of your address assignments, but if you specify the host, it > will deny it due to the deny known-hosts. The second pool I'm using > for static assignments, but it's crucial to have the deny > unknown-clients or else anybody you deny up top will be able to get an > ip here. > As usual, questions, comments anything else is always welcome. Nice work, Eric. We knew you had it in you, if you stuck with it long enough. ;) Thanks for sharing your solution, too. ....Bill

June 3, 2006

Re: [Wlug] dhcpd question

by Eric Martin

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 #Global Declarations ddns-update-style ad-hoc; option domain-name "home.local"; default-lease-time 604800; # Default Lease 1 Week max-lease-time 1209600; # Max Lease 2 weeks authoritative; # We are the official DHCP Server for this network subnet 10.10.20.0 netmask 255.255.255.0 { authoritative; # Everybody in here will not get an ip whatsoever pool { range 10.10.20.20 10.10.20.127; deny known-clients; host slide { hardware ethernet 00:c0:9f:15:d7:3f; } } pool { range 10.10.20.128 10.10.20.253; deny unknown-clients; host fixed { hardware ethernet 00:11:22:33:44:55; # fixed-address 10.10.20.25; } } } Basically what you want is at least two pools. The first pool will do the most of your address assignments, but if you specify the host, it will deny it due to the deny known-hosts. The second pool I'm using for static assignments, but it's crucial to have the deny unknown-clients or else anybody you deny up top will be able to get an ip here. As usual, questions, comments anything else is always welcome. Jared Greenwald wrote: > So, why don't you post the answer so that others may benefit from > it? > > -Jared > > On 6/2/06, Eric Martin <freak4uxxx(a)gmail.com> wrote: I figured it > out. Thanks to all who helped point me in the right direction. > The man page was just really hard to grasp until I took a few > breaks and took a shot in the dark. > > Theo Van Dinter wrote: >>>> On Fri, Jun 02, 2006 at 12:22:22PM -0700, Mike Leo wrote: >>>>> could you just assign that MAC a bad IP setup? like the >>>>> wrong netmask or something? Would that solve your problem? >>>>> >>>> fwiw, I believe the "correct" method is listed in the >>>> dhcpd.conf man page. Look for "ALLOW AND DENY WITHIN POOL >>>> DECLARATIONS". there's a way to do allow/deny. without >>>> digging further, I'd guess you make a class with the mac >>>> addr's you don't want getting addresses, then deny the class. >>>> >>>> >>>> >>>> > ---------------------------------------------------------------------- > >>>> >>>> >>>> >>>> _______________________________________________ Wlug mailing >>>> list Wlug(a)mail.wlug.org >>>> http://mail.wlug.org/mailman/listinfo/wlug >>> > _______________________________________________ Wlug mailing list > Wlug(a)mail.wlug.org http://mail.wlug.org/mailman/listinfo/wlug >>> >> _______________________________________________ Wlug mailing list >> Wlug(a)mail.wlug.org http://mail.wlug.org/mailman/listinfo/wlug > -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.2 (GNU/Linux) iD8DBQFEgW5baI8VEtSi4H8RAltyAJ4hPopL2xxIq8CpveaX8FAWv262zgCgjxCT 0xzC1YuLntipH0LvZ99FfRU= =D3Kf -----END PGP SIGNATURE-----

June 3, 2006

Re: [Wlug] Children Computer Camps

by Chuck Anderson

On Fri, Jun 02, 2006 at 11:14:33AM -0400, Yury I Vashugin wrote: > Does anyone know any computer camps for children in Worcester-Boston > Area? Thank you. I know WPI holds many summer camps for children. I'm not sure if computer camp is one of them, but it may be worth checking out.

June 3, 2006

Re: [Wlug] dhcpd question

by Jared Greenwald

So, why don't you post the answer so that others may benefit from it? -Jared On 6/2/06, Eric Martin <freak4uxxx(a)gmail.com> wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > I figured it out. Thanks to all who helped point me in the right > direction. The man page was just really hard to grasp until I took a > few breaks and took a shot in the dark. > > Theo Van Dinter wrote: > > On Fri, Jun 02, 2006 at 12:22:22PM -0700, Mike Leo wrote: > >> could you just assign that MAC a bad IP setup? like the wrong > >> netmask or something? Would that solve your problem? > > > > fwiw, I believe the "correct" method is listed in the dhcpd.conf > > man page. Look for "ALLOW AND DENY WITHIN POOL DECLARATIONS". > > there's a way to do allow/deny. without digging further, I'd guess > > you make a class with the mac addr's you don't want getting > > addresses, then deny the class. > > > > > > ---------------------------------------------------------------------- > > > > > > > > _______________________________________________ Wlug mailing list > > Wlug(a)mail.wlug.org http://mail.wlug.org/mailman/listinfo/wlug > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.2.2 (GNU/Linux) > > iD8DBQFEgOB8aI8VEtSi4H8RAgN1AJ9xZaS0tDZq0w1cC6nSX5OMZ69s/ACgivCU > DIOlMNNaSdkUwjevEadaf6E= > =yxwf > -----END PGP SIGNATURE----- > > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org > http://mail.wlug.org/mailman/listinfo/wlug >

June 3, 2006

Re: [Wlug] dhcpd question

by Eric Martin

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I figured it out. Thanks to all who helped point me in the right direction. The man page was just really hard to grasp until I took a few breaks and took a shot in the dark. Theo Van Dinter wrote: > On Fri, Jun 02, 2006 at 12:22:22PM -0700, Mike Leo wrote: >> could you just assign that MAC a bad IP setup? like the wrong >> netmask or something? Would that solve your problem? > > fwiw, I believe the "correct" method is listed in the dhcpd.conf > man page. Look for "ALLOW AND DENY WITHIN POOL DECLARATIONS". > there's a way to do allow/deny. without digging further, I'd guess > you make a class with the mac addr's you don't want getting > addresses, then deny the class. > > > ---------------------------------------------------------------------- > > > > _______________________________________________ Wlug mailing list > Wlug(a)mail.wlug.org http://mail.wlug.org/mailman/listinfo/wlug -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.2 (GNU/Linux) iD8DBQFEgOB8aI8VEtSi4H8RAgN1AJ9xZaS0tDZq0w1cC6nSX5OMZ69s/ACgivCU DIOlMNNaSdkUwjevEadaf6E= =yxwf -----END PGP SIGNATURE-----

June 3, 2006

Re: [Wlug] dhcpd question

by Eric Martin

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 So I am barking up the right tree. I can't get it to work yet, but it's good to know I'm on the right path. Thank you to everybody for helping. Just so everyone knows I'm listing wlug under my resources that helped me. (it's part of the class to list your resources for *everything*). Theo Van Dinter wrote: > On Fri, Jun 02, 2006 at 12:22:22PM -0700, Mike Leo wrote: >> could you just assign that MAC a bad IP setup? like the wrong >> netmask or something? Would that solve your problem? > > fwiw, I believe the "correct" method is listed in the dhcpd.conf > man page. Look for "ALLOW AND DENY WITHIN POOL DECLARATIONS". > there's a way to do allow/deny. without digging further, I'd guess > you make a class with the mac addr's you don't want getting > addresses, then deny the class. > > > ---------------------------------------------------------------------- > > > _______________________________________________ Wlug mailing list > Wlug(a)mail.wlug.org http://mail.wlug.org/mailman/listinfo/wlug -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.2 (GNU/Linux) iD8DBQFEgMzYaI8VEtSi4H8RAoKQAJ0Q/E++Ox/o0/jZ7T1/ROAuyMd/IwCfbvmo aNsJfvp1xqvzubF0HwQiMSQ= =4WlG -----END PGP SIGNATURE-----

June 2, 2006