* On 2019 09 Mar 18:09 -0600, Olaf Meeuwissen wrote: > All the info I have seen on this topic in the thread is consistent with > hostid returning the "mangled" IP address belonging to the machine's > current hostname. This is normally set from /etc/hostname. That file > is created during installation. The IP address is in /etc/hosts. > > Taking 007f0100 as an example, swapping bytes in pairs gives 7f000001 > which gives 127.0.0.1. For 007f0101 you get 127.0.1.1. > > I just tried the following on my machine > > $ sudo hostname yoda # anything different from what you have now > $ hostid # this is silent for a while and then says > 00000000 > > Presumably, DNS times out and then you get whatever the code used to > initialize the return value. > > Trying to revert my change > > $ sudo hostname quark # this ponders things for a while and says > sudo: unable to resolve host yoda > $ hostid > 007f0101 > > Please note that the hostname command does *not* modify the contents of > /etc/hostname. To persist changes across reboots you'll need to edit > /etc/hostname yourself.
It looks like I have an exception: pi@aprxpi:~$ cat /etc/os-release PRETTY_NAME="Raspbian GNU/Linux 8 (jessie)" NAME="Raspbian GNU/Linux" VERSION_ID="8" VERSION="8 (jessie)" ID=raspbian ID_LIKE=debian HOME_URL="http://www.raspbian.org/" SUPPORT_URL="http://www.raspbian.org/RaspbianForums" BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs" pi@aprxpi:~$ ip address 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether b8:27:eb:8b:f3:1c brd ff:ff:ff:ff:ff:ff inet 192.168.25.61/24 brd 192.168.25.255 scope global eth0 valid_lft forever preferred_lft forever inet6 fd5d:beb2:2c86:0:ba27:ebff:fe8b:f31c/64 scope global mngtmpaddr dynamic valid_lft forever preferred_lft forever inet6 2001:470:1f0f:9fa:ba27:ebff:fe8b:f31c/64 scope global mngtmpaddr dynamic valid_lft forever preferred_lft forever inet6 fe80::ba27:ebff:fe8b:f31c/64 scope link valid_lft forever preferred_lft forever 4: ax0: <BROADCAST,NOARP,UP,LOWER_UP> mtu 512 qdisc pfifo_fast state UNKNOWN group default qlen 10 link/ax25 9c:60:9c:84:40:40:74 brd a2:a6:a8:40:40:40:00 pi@aprxpi:~$ hostid a8c03d19 pi@aprxpi:~$ hostname aprxpi.lan pi@aprxpi:~$ cat /etc/hosts 127.0.0.1 localhost 127.0.1.1 aprxpi pi@aprxpi:~$ ll /etc/host* -rw-r--r-- 1 root root 9 Aug 7 2006 /etc/host.conf -rw-r--r-- 1 root root 11 Mar 11 2018 /etc/hostname -rw-r--r-- 1 root root 37 Jun 18 2018 /etc/hosts -rw-r--r-- 1 root root 411 Mar 11 2016 /etc/hosts.allow -rw-r--r-- 1 root root 711 Mar 11 2016 /etc/hosts.deny On this particular machine the hostid is consistent with the IPv4 address of eth0. - Nate -- "The optimist proclaims that we live in the best of all possible worlds. The pessimist fears this is true." Web: http://www.n0nb.us GPG key: D55A8819 GitHub: N0NB
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