Udpcast February 2003

udpcast@udpcast.linux.lu

3 participants
3 discussions

RE: Suse 7.3 Boot Disk
by Mike McCall 26 Feb '03

26 Feb '03

In regard to the Suse 7.3 boot disk and its issues with APIC (noted here: http://www.udpcast.linux.lu/pipermail/udpcast/2002/000008.html), I believe that the kernel is the problem. When I replaced the kernel on the boot disk with one from the latest SuSe boot disk, 8.1, I did not receive the above mentioned error. However, I am still having problems with the network card being detected with the UDPcast CD, although it is detected with the SuSe 8.1 boot disk. Can anyone with a working SuSe 8.1 installation recompile linuxrc, and possibly post the files? I really like the simplicity of the pre-made disks, and would love to use them. Thanks for your help. Mike McCall Computer Technician Rio Rancho Public Schools (505)896-5996 x231

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Re: [Udpcast] (no subject)
by Matthew Richardson 04 Feb '03

04 Feb '03

> Our router equipment allows for multicast, however the > broadcast discovery packets are killed. So, it seems > that I'm not able to image a machine on say > 192.168.6.X subnet from 192.168.7.X subnet. > > Am I just missing an option, or is it possible to > specify an IP address that the clients can listen to, > or possibly a way to specify a list of IPs to include > in the multicast offer? I've been trying to get Multicasting to work in my department across subnets, and so far to no avail. The full list of options at: http://alain.knaff.lu/udpcast/cmd.html Suggests the use of TTL, along with mcast-all-addr (control address) and mcast-addr (data address). "By default mcast-all-addr is the Ethernet broadcast address if ttl is 1, and 224.0.0.1 otherwise" Note that mcast-all-addr must be set on both sender and receiver. However, I haven't been able to get this to work - I've been assured that multicasting is switched on on our router, but I haven't tried packet sniffing or extending the ttl as well - if anyone else has this working can they post a 'howto'? > O.K. I'm on a roll here today. One more question. > > I'm looking at creating a FreeBSD utility CD that > includes the udpcast program. We've been using a linux boot disk here to get machines built - basically it boots into linux (using Syslinux), then loads networking and gets everything else it needs into a local ramdisk (IDE drivers, applications etc) We've used a combination of dd.gz, parted and udp-sender to multicast an image to several machines and resize thir partitions (note you can use tee and named pipes with udp-sender so that is multicasts the image and writes to its own hard drive - meaning you can use a lab machine as the sender, getting round the subnet multicast issue. We're still at the development stage, but it all seems to be working well. Good to know there are other people out there using this great tool. Matthew ===================================================== Matthew Richardson School of Engineering and Electronics, The University of Edinburgh, King's Buildings, Mayfield Rd, Edinburgh EH9 3JL ----------------------------------------------------- M.Richardson(a)ed.ac.uk =====================================================

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Re: [Udpcast] (no subject)
by Alain Knaff 03 Feb '03

03 Feb '03

On Monday 03 February 2003 20:09, Peter W Schmiedeskamp wrote: [...] > Our router equipment allows for multicast, however the > broadcast discovery packets are killed. So, it seems > that I'm not able to image a machine on say > 192.168.6.X subnet from 192.168.7.X subnet. > > Am I just missing an option, or is it possible to > specify an IP address that the clients can listen to, > or possibly a way to specify a list of IPs to include > in the multicast offer? > > I've tried the TTL option, but it is at the router > level that a broadcast offer is killed. > > -Peter Unfortunately, without full multicast support from the router, it's not possible to use multicast accross subnets. There are possibilities to use a different multicast address for the discovery packet (-M option, to be given both to the sender and the receiver), just in case the router selectively blocked address 224.0.0.1 but let pass other addresses. However, support for this alternative is incomplete right now: - on the server, you also need to supply --async and --max-bitrate options. Preferably --fec too. - receivers must be ready before sender. ./udp-sender --max-bitrate 10m --ttl 2 -f /dev/zero -M 224.1.2.3 --fec 8x8 ./udp-receiver --ttl 2 -f /dev/zero -M 224.1.2.3 [...] > I try to build the software on FreeBSD, but it fails. > It seems that udpcast uses getopt.h instead of > unistd.h for handling the command line options. Maybe you could try just replacing every occurrence of #include <getopt.h> with #include <unistd.h> You might also need to replace the calls to getopt_long by calls to getopt. This would make all options that have no one-letter shorthand inaccessible, but those options are rarely used anyways, thus this would not be such a big issue. [...] > Was there much magic in porting to > Cygwin? Cygwin seems to try to duplicate the Linux > included headers like getopt.h. Most Cygwin changes are due to a slightly different network API, and due to a less precise timer granularity. [...] > Thanks a million. I've also got a tip for creating compressed system > images: > > Zero out the harddrive before installing the OS and other software on the > machine from which the snapshot will be taken. This will make sure the > disk is blank. When you are compressing the image, those zeros scrunch > down pretty small! IBM has a tool for zeroing the harddisk called > wipe(http://service.boulder.ibm.com/storage/hddtech/wipe.exe). Otherwise, > booting from a Linux / Unix floppy and doing a 'dd if=/dev/zero > of=/dev/hdX' will do it too. This wipe tool is indeed very interesting, especially if your Windows is on an NTFS partition, which is not as easy to access from linux. Thanks for the pointer. Regards, Alain

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Udpcast February 2003