Re: Default DNS lookup command?
On 31/10/23 16:27, Max Nikulin wrote: On 30/10/2023 14:03, Richard Hector wrote: On 24/10/23 06:01, Max Nikulin wrote: getent -s dns hosts zircon Ah, thanks. But I don't feel too bad about not finding that ... 'service' is not defined in that file, 'dns' doesn't occur, and searching for 'hosts' doesn't give anything useful either. I guess reading nsswitch.conf(5) is required. Do you mean that "hosts" entry in your /etc/nsswitch.conf lacks "dns"? Even systemd nss plugins recommend to keep it as a fallback. If you get no results then your resolver or DNS server may not be configured to resolve single-label names. Try some full name getent -s dns ahosts debian.org Sorry for the confusion (and delay) - I think I was referring to the getent man page, rather than the config file. Richard
Re: Default DNS lookup command?
On 30/10/2023 14:03, Richard Hector wrote: On 24/10/23 06:01, Max Nikulin wrote: getent -s dns hosts zircon Ah, thanks. But I don't feel too bad about not finding that ... 'service' is not defined in that file, 'dns' doesn't occur, and searching for 'hosts' doesn't give anything useful either. I guess reading nsswitch.conf(5) is required. Do you mean that "hosts" entry in your /etc/nsswitch.conf lacks "dns"? Even systemd nss plugins recommend to keep it as a fallback. If you get no results then your resolver or DNS server may not be configured to resolve single-label names. Try some full name getent -s dns ahosts debian.org
Re: Default DNS lookup command?
On 24/10/23 06:01, Max Nikulin wrote: On 22/10/2023 18:39, Richard Hector wrote: But not strictly a DNS lookup tool: richard@zircon:~$ getent hosts zircon 127.0.1.1 zircon.lan.walnut.gen.nz zircon That's from my /etc/hosts file, and overrides DNS. I didn't see an option in the manpage to ignore /etc/hosts. getent -s dns hosts zircon However /etc/resolv.conf may point to local systemd-resolved server or to dnsmasq started by NetworkManager and they read /etc/hosts by default. Ah, thanks. But I don't feel too bad about not finding that ... 'service' is not defined in that file, 'dns' doesn't occur, and searching for 'hosts' doesn't give anything useful either. I guess reading nsswitch.conf(5) is required. Thanks, Richard
Re: Default DNS lookup command?
On 22/10/2023 18:39, Richard Hector wrote: But not strictly a DNS lookup tool: richard@zircon:~$ getent hosts zircon 127.0.1.1 zircon.lan.walnut.gen.nz zircon That's from my /etc/hosts file, and overrides DNS. I didn't see an option in the manpage to ignore /etc/hosts. getent -s dns hosts zircon However /etc/resolv.conf may point to local systemd-resolved server or to dnsmasq started by NetworkManager and they read /etc/hosts by default. I haven't found a way to get just DNS results, without pulling in extra software. Usual task for application is to resolve hostname and enough methods besides DNS may be used: multicast DNS, LLMNR, etc. If you need a debug tool then you should install it. On the other hand it is desperate when a feature is implemented, but not exposed to users.
Re: Default DNS lookup command?
On 23/10/2023 20:52, David Wright wrote: AFAICT, if you don't have busybox installed, then I think it's likely that you removed it yourself. Or it is a LXC container installed using the "download" template. It uses systemd-networkd and systemd-resolved. I have never tried qemu with kernel and initrd loaded from host, so related tools are not necessary inside VM. So for original requirement "on any Debian Bullseye or Bookworm install" I would not neglect resolvectl when systemd-resolved is active.
Re: Default DNS lookup command?
On Sun 22 Oct 2023 at 11:07:05 (+0700), Max Nikulin wrote: > On 21/10/2023 22:58, David Wright wrote: > > On Sat 21 Oct 2023 at 17:35:21 (+0200), Reiner Buehl wrote: > > > is there a DNS lookup command that is installed by default on any > > > Debian Bullseye or Bookworm install? > > > > nslookup is in busybox. > > busybox is an optional package, so it may be absent. "getent hosts" > from Greg's message is better in this sense. If systemd-resolved is > configured on a particular instance then > > resolvectl query debian.org > > may be an option. AFAICT, if you don't have busybox installed, then I think it's likely that you removed it yourself. The d-i initrd has busybox already installed, and most people will see something like this in its log: # head -n2 /var/log/installer/syslog Jul 26 19:17:07 syslogd started: BusyBox v1.35.0 Jul 26 19:17:07 kernel: klogd started: BusyBox v1.35.0 (Debian 1:1.35.0-4+b3) # If the following file is still available (the one with the highest generation number), you can see that busybox is typically the third package to be installed by APT. (If the file has been rotated away, just search for "busybox" in the file above.) # zcat /var/log/apt/history.log.2.gz | head Start-Date: 2023-07-26 19:30:49 Commandline: apt-get -o APT::Status-Fd=4 -o APT::Keep-Fds::=5 -o APT::Keep-Fds::=6 -q -y --no-remove install locales Install: locales:i386 (2.36-9), libc-l10n:i386 (2.36-9, automatic) End-Date: 2023-07-26 19:30:56 Start-Date: 2023-07-26 14:31:14 Commandline: apt-get -o APT::Status-Fd=4 -o APT::Keep-Fds::=5 -o APT::Keep-Fds::=6 -q -y --no-remove install busybox Install: busybox:i386 (1:1.35.0-4+b3) End-Date: 2023-07-26 14:31:16 # I suppose preseed experts might be able to prevent that from happening, though to what purpose, IDK. I can only assume that its Priority is set to Optional so that it's easily removable if not required. I don't see many reasons that systemd-resolved would get installed unless you specifically asked for it, so I'd hardly call it "installed by default". Cheers, David.
Re: Default DNS lookup command?
On 22/10/23 04:56, Greg Wooledge wrote: On Sat, Oct 21, 2023 at 05:35:21PM +0200, Reiner Buehl wrote: is there a DNS lookup command that is installed by default on any Debian getent hosts NAME getent ahostsv4 NAME That said, you get much finer control from dedicated tools. That is a useful tool I should remember. But not strictly a DNS lookup tool: richard@zircon:~$ getent hosts zircon 127.0.1.1 zircon.lan.walnut.gen.nz zircon That's from my /etc/hosts file, and overrides DNS. I didn't see an option in the manpage to ignore /etc/hosts. I haven't found a way to get just DNS results, without pulling in extra software. Richard
Re: Default DNS lookup command?
On 21/10/2023 22:58, David Wright wrote: On Sat 21 Oct 2023 at 17:35:21 (+0200), Reiner Buehl wrote: is there a DNS lookup command that is installed by default on any Debian Bullseye or Bookworm install? nslookup is in busybox. busybox is an optional package, so it may be absent. "getent hosts" from Greg's message is better in this sense. If systemd-resolved is configured on a particular instance then resolvectl query debian.org may be an option.
Re: Default DNS lookup command?
Perfect! Then I just need to add an alias to my profile and can use nslookup :-) On 21.10.23 17:58, David Wright wrote: On Sat 21 Oct 2023 at 17:35:21 (+0200), Reiner Buehl wrote: > is there a DNS lookup command that is installed by default on any > Debian Bullseye or Bookworm install? Something that doesn't require as > much dependencies as bind9-utils (which provides dig and nslookup) or > bind9-host? nslookup is in busybox. Type: $ busybox nslookup $ busybox nslookup debian.org Cheers, David.
Re: Default DNS lookup command?
Hello, it's not really answer to your question, but for simple things like IP-Addresses you can use getent ahosts, getent hosts or ping directly. Best Regards, Juri Grabowski
Re: Default DNS lookup command?
On Sat 21 Oct 2023 at 17:35:21 (+0200), Reiner Buehl wrote: > is there a DNS lookup command that is installed by default on any > Debian Bullseye or Bookworm install? Something that doesn't require as > much dependencies as bind9-utils (which provides dig and nslookup) or > bind9-host? nslookup is in busybox. Type: $ busybox nslookup $ busybox nslookup debian.org Cheers, David.
Re: Default DNS lookup command?
On Sat, Oct 21, 2023 at 05:35:21PM +0200, Reiner Buehl wrote: > is there a DNS lookup command that is installed by default on any Debian getent hosts NAME getent ahostsv4 NAME That said, you get much finer control from dedicated tools.
