Bonjour,
Comme il est clairement expliqué ici
https://access.redhat.com/solutions/3641601, la commande "getent hosts HOST" n'a pas forcément le comportement
attendu lorsqu'il y a une résolution de HOST en IPv6 par le dns.
La consigne de priorité de /etc/nsswitch.conf
hosts: files dns
n''étant pas respectée puisque malgré la présence de HOST dans /etc/hosts,
c'est malgré tout la résolution DNS qui agit.
Je le redis, c'est uniquement quand la résolution est possible en IPv6 via
DNS. Dans tous les autres cas, le résultat est bien celui attendu.
Est-ce que ça parle à quelqu'un ? Si oui, aurait-il alors une idée de
contournement autre que de ne pas utiliser getent ?
Pour confirmation, le strace correspondant :
# strace getent hosts HOST
execve("/usr/bin/getent", ["getent", "hosts", "HOST"], 0x7ffe75a192d0 /* 55
vars */) = 0
brk(NULL) = 0x559bb7b7e000
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (Aucun fichier ou
dossier de ce nom)
openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=196698, ...}) = 0
mmap(NULL, 196698, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fca284ed000
close(3) = 0
openat(AT_FDCWD, "/usr/lib64/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3,
"\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260e\2\0\0\0\0\0"..., 832)
= 832
pread64(3,
"\6\0\0\0\4\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0"..., 784,
64) = 784
fstat(3, {st_mode=S_IFREG|0755, st_size=1990912, ...}) = 0
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0x7fca284eb000
pread64(3,
"\6\0\0\0\4\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0"..., 784,
64) = 784
mmap(NULL, 2018232, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) =
0x7fca282fe000
mmap(0x7fca28322000, 1470464, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|
MAP_DENYWRITE, 3, 0x24000) = 0x7fca28322000
mmap(0x7fca28489000, 344064, PROT_READ, MAP_PRIVATE|MAP_FIXED|
MAP_DENYWRITE, 3, 0x18b000) = 0x7fca28489000
mmap(0x7fca284dd000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|
MAP_DENYWRITE, 3, 0x1df000) = 0x7fca284dd000
mmap(0x7fca284e3000, 31672, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|
MAP_ANONYMOUS, -1, 0) = 0x7fca284e3000
close(3) = 0
mmap(NULL, 12288, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0x7fca282fb000
arch_prctl(ARCH_SET_FS, 0x7fca282fb740) = 0
set_tid_address(0x7fca282fba10) = 10365
set_robust_list(0x7fca282fba20, 24) = 0
rseq(0x7fca282fc060, 0x20, 0, 0x53053053) = 0
mprotect(0x7fca284dd000, 16384, PROT_READ) = 0
mprotect(0x559ba322a000, 4096, PROT_READ) = 0
mprotect(0x7fca28552000, 8192, PROT_READ) = 0
prlimit64(0, RLIMIT_STACK, NULL, {rlim_cur=8192*1024,
rlim_max=RLIM64_INFINITY}) = 0
munmap(0x7fca284ed000, 196698) = 0
getrandom("\x75\xba\x7d\x57\xd7\x40\x4a\x51", 8, GRND_NONBLOCK) = 8
brk(NULL) = 0x559bb7b7e000
brk(0x559bb7b9f000) = 0x559bb7b9f000
openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=3728992, ...}) = 0
mmap(NULL, 3728992, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fca27f6c000
close(3) = 0
newfstatat(AT_FDCWD, "/etc/resolv.conf", {st_mode=S_IFREG|0644,
st_size=192, ...}, 0) = 0
openat(AT_FDCWD, "/etc/host.conf", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=825, ...}) = 0
read(3, "# /etc/host.conf:\n\n# The file /"..., 4096) = 825
read(3, "", 4096) = 0
close(3) = 0
futex(0x7fca284e968c, FUTEX_WAKE_PRIVATE, 2147483647) = 0
openat(AT_FDCWD, "/etc/resolv.conf", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=192, ...}) = 0
read(3, "# Generated by dhcpcd from wlan0"..., 4096) = 192
read(3, "", 4096) = 0
fstat(3, {st_mode=S_IFREG|0644, st_size=192, ...}) = 0
close(3) = 0
newfstatat(AT_FDCWD, "/etc/nsswitch.conf", {st_mode=S_IFREG|0644,
st_size=2092, ...}, 0) = 0
newfstatat(AT_FDCWD, "/", {st_mode=S_IFDIR|0755, st_size=4096, ...}, 0) = 0
openat(AT_FDCWD, "/etc/nsswitch.conf", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=2092, ...}) = 0
read(3, "#\n# /etc/nsswitch.conf\n#\n# An ex"..., 4096) = 2092
read(3, "", 4096) = 0
fstat(3, {st_mode=S_IFREG|0644, st_size=2092, ...}) = 0
close(3) = 0
openat(AT_FDCWD, "/etc/hosts", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=2731, ...}) = 0
lseek(3, 0, SEEK_SET) = 0
read(3, "# /etc/hosts: Local Host Databas"..., 4096) = 2731
read(3, "", 4096) = 0
close(3) = 0
fstat(1, {st_mode=S_IFIFO|0600, st_size=0, ...}) = 0
write(1, "IPV6 HOST\n", 27IPV6 HOST
) = 27
exit_group(0) = ?
+++ exited with 0 +++
PS : inutile de mettre en cause le fait que HOST resolve localement
autrement que par dns. Ce n'est pas le sujet.
getent host ipv6 et priorité files
Re: getent host ipv6 et priorité files