5 ms·

On Arch, I get "ping: Warning: IPv6 link-local address on ICMP datagram socket may require ifname or scope-id => use: address%<ifname|scope-id>", and it doesn't

by Latty 2y ago

On Arch, I get "ping: Warning: IPv6 link-local address on ICMP datagram socket may require ifname or scope-id => use: address%<ifname|scope-id>", and it doesn't work unless I do so.

lucb1e 2y ago
Oh, interesting! Which ping have you got? Mine comes from the iputils-ping Debian package, which the man page confirms it's part of some broader iputils set of tools. I see there is also inetutils-ping which provides the same /bin/ping and /bin/ping6 commands, is that perhaps the one you've got? For anyone wanting to replicate this "provides" query on Debian, I use `apt-file search /bin/ping` to list what packages have a file with that name -- this will also match `/usr/bin/ping6` (both prefixes and suffixes will match) but that was fine in this case. (If you just do `apt search ping` or something, you get a huge list of any package mentioning the word ping, which may be what you want when searching for something more broadly; and if you use `apt search /bin/ping` it comes up empty because it doesn't have file path data.) Edit: now that I had looked up which utility it is, I figured I'd check the "is documentation enough" on how it finds which interface to use. It looks to me like it is `getaddrinfo` that decides it: https://github.com/iputils/iputils/blob/master/ping/ping.c#L648-L681 https://github.com/iputils/iputils/blob/master/ping/ping.c#L...
- Latty 2y ago
  Yeah, I'm just using Arch's default iputils: > pkgfile $(which ping) core/iputils That doesn't provide a `ping6`, presumably as `ping -6` is the preferred solution.
aftbit 2y ago
I tried this on Arch and it didn't work at all. $ ping -6 ff02::1%eth2 Did I miss some kernel tunable or nftables setting? Unicast ping works fine.
- Latty 2y ago
  Do you have a link-local v6 address on that device? My first attempt `ping ff02::1%enp9s0` didn't work because I use VLANs and don't actually get addresses on the base device, using the VLAN virtual device (in my case `ping ff02::1%lan`) worked for me. You shouldn't need `-6`, given it's a v6 address.
  - aftbit 2y ago
    Yea I figured -6 was superfluous but I put it in because another commenter made a big deal out of ping vs ping6 (a distinction that's been gone in Arch for a while). I do have a link local address directly on that NIC. I also use VLANs sometimes, but none are configured right now on this link. Slightly edited below to hide my MAC but: $ ip -6 address show dev eth2 | grep link inet6 fe80::aef0:b837:fafa:fefe/64 scope link noprefixroute The same command works fine on my Debian and OpenWRT boxes, but not on my Arch desktop.
- cchance 2y ago
  on osx it's .... ping6 -I en0 ff02::1 maybe different way to specify the interface

by Latty 2y ago

On Arch, I get "ping: Warning: IPv6 link-local address on ICMP datagram socket may require ifname or scope-id => use: address%<ifname|scope-id>", and it doesn't work unless I do so.

lucb1e 2y ago

Oh, interesting! Which ping have you got? Mine comes from the iputils-ping Debian package, which the man page confirms it's part of some broader iputils set of tools. I see there is also inetutils-ping which provides the same /bin/ping and /bin/ping6 commands, is that perhaps the one you've got? For anyone wanting to replicate this "provides" query on Debian, I use `apt-file search /bin/ping` to list what packages have a file with that name -- this will also match `/usr/bin/ping6` (both prefixes and suffixes will match) but that was fine in this case. (If you just do `apt search ping` or something, you get a huge list of any package mentioning the word ping, which may be what you want when searching for something more broadly; and if you use `apt search /bin/ping` it comes up empty because it doesn't have file path data.) Edit: now that I had looked up which utility it is, I figured I'd check the "is documentation enough" on how it finds which interface to use. It looks to me like it is `getaddrinfo` that decides it: https://github.com/iputils/iputils/blob/master/ping/ping.c#L648-L681 https://github.com/iputils/iputils/blob/master/ping/ping.c#L...

Latty 2y ago
Yeah, I'm just using Arch's default iputils: > pkgfile $(which ping) core/iputils That doesn't provide a `ping6`, presumably as `ping -6` is the preferred solution.

aftbit 2y ago

I tried this on Arch and it didn't work at all. $ ping -6 ff02::1%eth2 Did I miss some kernel tunable or nftables setting? Unicast ping works fine.

Latty 2y ago
Do you have a link-local v6 address on that device? My first attempt `ping ff02::1%enp9s0` didn't work because I use VLANs and don't actually get addresses on the base device, using the VLAN virtual device (in my case `ping ff02::1%lan`) worked for me. You shouldn't need `-6`, given it's a v6 address.
- aftbit 2y ago
  Yea I figured -6 was superfluous but I put it in because another commenter made a big deal out of ping vs ping6 (a distinction that's been gone in Arch for a while). I do have a link local address directly on that NIC. I also use VLANs sometimes, but none are configured right now on this link. Slightly edited below to hide my MAC but: $ ip -6 address show dev eth2 | grep link inet6 fe80::aef0:b837:fafa:fefe/64 scope link noprefixroute The same command works fine on my Debian and OpenWRT boxes, but not on my Arch desktop.
cchance 2y ago
on osx it's .... ping6 -I en0 ff02::1 maybe different way to specify the interface