Bug#537271: debian-installer: network may not be usable as soon as link is up
On Thursday, July 16, 2009 05:39:24 pm you wrote: the debian-installer seems to assume that the network is usable as soon as the link comes up, which may not be the case if the 802.1d spanning tree protocol is in use, in which case it can be up to ~30 seconds before the switch port will forward ethernet frames. i've noticed that trying to preseed a network install on a machine attached to an STP-enabled switch usually fails since as soon as the network link is up, d-i attempts to perform a reverse DNS lookup and fetch the preseed.cfg file via HTTP, both of which timeout and fail before the switch port the machine is attached to enters the forwarding state. a nice strategy to detect if the network is usable might be to send ARP requests for the default gateway's IP address and consider the network up only after the default gateway is reachable. it looks like there is a busybox version of the arping utility that could help accomplish this. Quick dirty workaround if enabling arping in busybox (or implementing the same in C in netcfg itself) is not an option, may also be to simply increase the number of ARP retries. echo 60 /proc/sys/net/ipv4/neigh/eth0/mcast_solicit -- Yours sincerely, Floris Bos -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
Bug#537271: debian-installer: network may not be usable as soon as link is up
Package: debian-installer Version: 20090123lenny1 hi, the debian-installer seems to assume that the network is usable as soon as the link comes up, which may not be the case if the 802.1d spanning tree protocol is in use, in which case it can be up to ~30 seconds before the switch port will forward ethernet frames. i've noticed that trying to preseed a network install on a machine attached to an STP-enabled switch usually fails since as soon as the network link is up, d-i attempts to perform a reverse DNS lookup and fetch the preseed.cfg file via HTTP, both of which timeout and fail before the switch port the machine is attached to enters the forwarding state. a nice strategy to detect if the network is usable might be to send ARP requests for the default gateway's IP address and consider the network up only after the default gateway is reachable. it looks like there is a busybox version of the arping utility that could help accomplish this. -- Robert Edmonds edmo...@debian.org signature.asc Description: Digital signature
Bug#537271: debian-installer: network may not be usable as soon as link is up
reassign 537271 netcfg thanks Quoting Robert Edmonds (edmo...@debian.org): a nice strategy to detect if the network is usable might be to send ARP requests for the default gateway's IP address and consider the network up only after the default gateway is reachable. it looks like there is a busybox version of the arping utility that could help accomplish this. Ready to implement this in netcfg? :-) PS: that would probably need some debconf stuff to implement a dialog saying something like Waiting for the network link I'd suggest to add such a detection *after* the first attempt to use the network fails... signature.asc Description: Digital signature
Bug#537271: debian-installer: network may not be usable as soon as link is up
Christian Perrier wrote: Quoting Robert Edmonds (edmo...@debian.org): a nice strategy to detect if the network is usable might be to send ARP requests for the default gateway's IP address and consider the network up only after the default gateway is reachable. it looks like there is a busybox version of the arping utility that could help accomplish this. Ready to implement this in netcfg? :-) maybe. it's python, right? where is the trunk? PS: that would probably need some debconf stuff to implement a dialog saying something like Waiting for the network link and some sort of error message if the default gateway doesn't respond after a long time. and it would have to be conditional on a default gateway being configured. i guess there is a pathological case where you could do a net install with servers that are all on the local network. I'd suggest to add such a detection *after* the first attempt to use the network fails... why? it's not optional for the gateway router to ignore ARP (unlike ICMP echo), or else it couldn't function as a router, so the check must succeed 100% of the time. and the attempts to use the network could fail for other reasons. -- Robert Edmonds edmo...@debian.org signature.asc Description: Digital signature
Bug#537271: debian-installer: network may not be usable as soon as link is up
Quoting Robert Edmonds (edmo...@debian.org): Ready to implement this in netcfg? :-) maybe. it's python, right? where is the trunk? Aha. Nothing in D-I is python. Too big stuff netcfg is implemented in C. It is one of the few parts in D-I that's coded in C. PS: that would probably need some debconf stuff to implement a dialog saying something like Waiting for the network link and some sort of error message if the default gateway doesn't respond after a long time. and it would have to be conditional on a default gateway being configured. i guess there is a pathological case where you could do a net install with servers that are all on the local network. I'd suggest to add such a detection *after* the first attempt to use the network fails... why? it's not optional for the gateway router to ignore ARP (unlike ICMP echo), or else it couldn't function as a router, so the check must succeed 100% of the time. and the attempts to use the network could fail for other reasons. That was just a (quite minor) suggestion, indeed..:-) signature.asc Description: Digital signature
