IPv6 partially broken under lx ubuntu 20.04

[sjorge]

root@artemis:~# ping6 blackdot.be
ping6: IPV6_RECVERR: Protocol not available

On older ubuntu it prints:

root@artemis:~# ping6 blackdot.be
WARNING: your kernel is veeery old. No problems.
PING blackdot.be(www.blackdot.be) 56 data bytes
64 bytes from www.blackdot.be: icmp_seq=1 ttl=246 time=6.29 ms
64 bytes from www.blackdot.be: icmp_seq=2 ttl=246 time=7.10 ms
^C
--- blackdot.be ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1000ms
rtt min/avg/max/mdev = 6.294/6.699/7.105/0.413 ms

I'm guessing whatever code path we end up in that prints the warning, is gone on ubuntu 20.04.

Having a IPv6 resolver as first nameserver in resolv.conf also results in a broken resolver.

[sjorge]

Pinging the zone from somewhere else does work, so I'm guessing it's a missing syscall.

[sjorge]

root@artemis:~# strace ping6 blackdot.be
execve("/usr/bin/ping6", ["ping6", "blackdot.be"], 0x7fffffeff578 /* 21 vars */) = 0
brk(NULL)                               = 0x1000
arch_prctl(0x3001 /* ARCH_??? */, 0x7fffffeff490) = -1 EINVAL (Invalid argument)
uname({sysname="Linux", nodename="artemis", ...}) = 0
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=13336, ...}) = 0
mmap(NULL, 13336, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fffef050000
close(3)                                = 0
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libcap.so.2", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\300#\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0644, st_size=31120, ...}) = 0
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fffef040000
mmap(NULL, 33112, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fffef030000
mprotect(0x7fffef032000, 20480, PROT_NONE) = 0
mmap(0x7fffef032000, 12288, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2000) = 0x7fffef032000
mmap(0x7fffef035000, 4096, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x5000) = 0x7fffef035000
mmap(0x7fffef037000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x6000) = 0x7fffef037000
close(3)                                = 0
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libgcrypt.so.20", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\200\305\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0644, st_size=1168056, ...}) = 0
mmap(NULL, 1171400, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fffeef11000
mmap(0x7fffeef1d000, 843776, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xc000) = 0x7fffeef1d000
mmap(0x7fffeefeb000, 249856, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xda000) = 0x7fffeefeb000
mmap(0x7fffef028000, 28672, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x116000) = 0x7fffef028000
close(3)                                = 0
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libresolv.so.2", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0 G\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0644, st_size=101320, ...}) = 0
mmap(NULL, 113280, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fffeeef4000
mprotect(0x7fffeeef8000, 81920, PROT_NONE) = 0
mmap(0x7fffeeef8000, 65536, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x4000) = 0x7fffeeef8000
mmap(0x7fffeef08000, 12288, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x14000) = 0x7fffeef08000
mmap(0x7fffeef0c000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x17000) = 0x7fffeef0c000
mmap(0x7fffeef0e000, 6784, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7fffeef0e000
close(3)                                = 0
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/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\360q\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
pread64(3, "\4\0\0\0\20\0\0\0\5\0\0\0GNU\0\2\0\0\300\4\0\0\0\3\0\0\0\0\0\0\0", 32, 848) = 32
pread64(3, "\4\0\0\0\24\0\0\0\3\0\0\0GNU\0\t\233\222%\274\260\320\31\331\326\10\204\276X>\263"..., 68, 880) = 68
fstat(3, {st_mode=S_IFREG|0755, st_size=2029224, ...}) = 0
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
pread64(3, "\4\0\0\0\20\0\0\0\5\0\0\0GNU\0\2\0\0\300\4\0\0\0\3\0\0\0\0\0\0\0", 32, 848) = 32
pread64(3, "\4\0\0\0\24\0\0\0\3\0\0\0GNU\0\t\233\222%\274\260\320\31\331\326\10\204\276X>\263"..., 68, 880) = 68
mmap(NULL, 2036952, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fffeed01000
mprotect(0x7fffeed26000, 1847296, PROT_NONE) = 0
mmap(0x7fffeed26000, 1540096, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x25000) = 0x7fffeed26000
mmap(0x7fffeee9e000, 303104, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x19d000) = 0x7fffeee9e000
mmap(0x7fffeeee9000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1e7000) = 0x7fffeeee9000
mmap(0x7fffeeeef000, 13528, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7fffeeeef000
close(3)                                = 0
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libgpg-error.so.0", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0`L\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0644, st_size=137584, ...}) = 0
mmap(NULL, 139872, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fffeecdd000
mmap(0x7fffeece1000, 77824, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x4000) = 0x7fffeece1000
mmap(0x7fffeecf4000, 40960, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x17000) = 0x7fffeecf4000
mmap(0x7fffeecfe000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x20000) = 0x7fffeecfe000
close(3)                                = 0
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fffeecd0000
arch_prctl(ARCH_SET_FS, 0x7fffeecd1040) = 0
mprotect(0x7fffeeee9000, 12288, PROT_READ) = 0
mprotect(0x7fffeecfe000, 4096, PROT_READ) = 0
mprotect(0x7fffeef0c000, 4096, PROT_READ) = 0
mprotect(0x7fffef028000, 8192, PROT_READ) = 0
mprotect(0x7fffef037000, 4096, PROT_READ) = 0
mprotect(0x7fffef436000, 4096, PROT_READ) = 0
mprotect(0x7fffef421000, 4096, PROT_READ) = 0
munmap(0x7fffef050000, 13336)           = 0
brk(NULL)                               = 0x1000
brk(0x22000)                            = 0x22000
prctl(PR_CAPBSET_READ, CAP_MAC_OVERRIDE) = -1 EINVAL (Invalid argument)
prctl(PR_CAPBSET_READ, CAP_IPC_OWNER)   = -1 EINVAL (Invalid argument)
prctl(PR_CAPBSET_READ, CAP_SETUID)      = -1 EINVAL (Invalid argument)
prctl(PR_CAPBSET_READ, CAP_FOWNER)      = -1 EINVAL (Invalid argument)
prctl(PR_CAPBSET_READ, CAP_DAC_OVERRIDE) = -1 EINVAL (Invalid argument)
prctl(PR_CAPBSET_READ, CAP_CHOWN)       = -1 EINVAL (Invalid argument)
capget({version=_LINUX_CAPABILITY_VERSION_3, pid=0}, NULL) = -1 EFAULT (Bad address)
capget({version=_LINUX_CAPABILITY_VERSION_3, pid=0}, {effective=1<<CAP_CHOWN|1<<CAP_DAC_OVERRIDE|1<<CAP_DAC_READ_SEARCH|1<<CAP_FOWNER|1<<CAP_FSETID|1<<CAP_KILL|1<<CAP_SETGID|1<<CAP_SETUID|1<<CAP_NET_BIND_SERVICE|1<<CAP_NET_ADMIN|1<<CAP_NET_RAW|1<<CAP_IPC_LOCK|1<<CAP_IPC_OWNER|1<<CAP_SYS_CHROOT|1<<CAP_SYS_ADMIN|1<<CAP_SYS_NICE|1<<CAP_SYS_RESOURCE|1<<CAP_AUDIT_WRITE|1<<CAP_AUDIT_CONTROL, permitted=1<<CAP_CHOWN|1<<CAP_DAC_OVERRIDE|1<<CAP_DAC_READ_SEARCH|1<<CAP_FOWNER|1<<CAP_FSETID|1<<CAP_KILL|1<<CAP_SETGID|1<<CAP_SETUID|1<<CAP_NET_BIND_SERVICE|1<<CAP_NET_ADMIN|1<<CAP_NET_RAW|1<<CAP_IPC_LOCK|1<<CAP_IPC_OWNER|1<<CAP_SYS_CHROOT|1<<CAP_SYS_ADMIN|1<<CAP_SYS_NICE|1<<CAP_SYS_RESOURCE|1<<CAP_AUDIT_WRITE|1<<CAP_AUDIT_CONTROL, inheritable=0}) = 0
capget({version=_LINUX_CAPABILITY_VERSION_3, pid=0}, NULL) = -1 EFAULT (Bad address)
capset({version=_LINUX_CAPABILITY_VERSION_3, pid=0}, {effective=0, permitted=1<<CAP_NET_ADMIN|1<<CAP_NET_RAW, inheritable=0}) = 0
prctl(PR_SET_KEEPCAPS, 1)               = 0
getuid()                                = 0
setuid(0)                               = 0
prctl(PR_SET_KEEPCAPS, 0)               = 0
getuid()                                = 0
geteuid()                               = 0
openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=3035952, ...}) = 0
mmap(NULL, 3035952, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fffee800000
close(3)                                = 0
capget({version=_LINUX_CAPABILITY_VERSION_3, pid=0}, NULL) = -1 EFAULT (Bad address)
capget({version=_LINUX_CAPABILITY_VERSION_3, pid=0}, {effective=0, permitted=1<<CAP_NET_ADMIN|1<<CAP_NET_RAW, inheritable=0}) = 0
capset({version=_LINUX_CAPABILITY_VERSION_3, pid=0}, {effective=1<<CAP_NET_RAW, permitted=1<<CAP_NET_ADMIN|1<<CAP_NET_RAW, inheritable=0}) = 0
socket(AF_INET6, SOCK_DGRAM, IPPROTO_ICMPV6) = -1 EACCES (Permission denied)
socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6) = 3
capget({version=_LINUX_CAPABILITY_VERSION_3, pid=0}, NULL) = -1 EFAULT (Bad address)
capget({version=_LINUX_CAPABILITY_VERSION_3, pid=0}, {effective=1<<CAP_NET_RAW, permitted=1<<CAP_CHOWN|1<<CAP_DAC_OVERRIDE|1<<CAP_DAC_READ_SEARCH|1<<CAP_FOWNER|1<<CAP_FSETID|1<<CAP_KILL|1<<CAP_SETGID|1<<CAP_SETUID|1<<CAP_NET_BIND_SERVICE|1<<CAP_NET_ADMIN|1<<CAP_NET_RAW|1<<CAP_IPC_LOCK|1<<CAP_IPC_OWNER|1<<CAP_SYS_CHROOT|1<<CAP_SYS_ADMIN|1<<CAP_SYS_NICE|1<<CAP_SYS_RESOURCE|1<<CAP_AUDIT_WRITE|1<<CAP_AUDIT_CONTROL, inheritable=0}) = 0
capset({version=_LINUX_CAPABILITY_VERSION_3, pid=0}, {effective=0, permitted=1<<CAP_CHOWN|1<<CAP_DAC_OVERRIDE|1<<CAP_DAC_READ_SEARCH|1<<CAP_FOWNER|1<<CAP_FSETID|1<<CAP_KILL|1<<CAP_SETGID|1<<CAP_SETUID|1<<CAP_NET_BIND_SERVICE|1<<CAP_NET_ADMIN|1<<CAP_NET_RAW|1<<CAP_IPC_LOCK|1<<CAP_IPC_OWNER|1<<CAP_SYS_CHROOT|1<<CAP_SYS_ADMIN|1<<CAP_SYS_NICE|1<<CAP_SYS_RESOURCE|1<<CAP_AUDIT_WRITE|1<<CAP_AUDIT_CONTROL, inheritable=0}) = 0
socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0) = 4
connect(4, {sa_family=AF_UNIX, sun_path="/var/run/nscd/socket"}, 110) = -1 ENOENT (No such file or directory)
close(4)                                = 0
socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0) = 4
connect(4, {sa_family=AF_UNIX, sun_path="/var/run/nscd/socket"}, 110) = -1 ENOENT (No such file or directory)
close(4)                                = 0
openat(AT_FDCWD, "/etc/nsswitch.conf", O_RDONLY|O_CLOEXEC) = 4
fstat(4, {st_mode=S_IFREG|0644, st_size=510, ...}) = 0
read(4, "# /etc/nsswitch.conf\n#\n# Example"..., 512) = 510
read(4, "", 512)                        = 0
close(4)                                = 0
stat("/etc/resolv.conf", {st_mode=S_IFREG|0755, st_size=87, ...}) = 0
openat(AT_FDCWD, "/etc/host.conf", O_RDONLY|O_CLOEXEC) = 4
fstat(4, {st_mode=S_IFREG|0644, st_size=92, ...}) = 0
read(4, "# The \"order\" line is only used "..., 512) = 92
read(4, "", 512)                        = 0
close(4)                                = 0
openat(AT_FDCWD, "/etc/resolv.conf", O_RDONLY|O_CLOEXEC) = 4
fstat(4, {st_mode=S_IFREG|0755, st_size=87, ...}) = 0
read(4, "search acheron.be mgmt.acheron.b"..., 512) = 87
read(4, "", 512)                        = 0
close(4)                                = 0
openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 4
fstat(4, {st_mode=S_IFREG|0644, st_size=13336, ...}) = 0
mmap(NULL, 13336, PROT_READ, MAP_PRIVATE, 4, 0) = 0x7fffeec80000
close(4)                                = 0
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libnss_files.so.2", O_RDONLY|O_CLOEXEC) = 4
read(4, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\3005\0\0\0\0\0\0"..., 832) = 832
fstat(4, {st_mode=S_IFREG|0644, st_size=51832, ...}) = 0
mmap(NULL, 79672, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 4, 0) = 0x7fffeec6b000
mmap(0x7fffeec6e000, 28672, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0x3000) = 0x7fffeec6e000
mmap(0x7fffeec75000, 8192, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0xa000) = 0x7fffeec75000
mmap(0x7fffeec77000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0xb000) = 0x7fffeec77000
mmap(0x7fffeec79000, 22328, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7fffeec79000
close(4)                                = 0
mprotect(0x7fffeec77000, 4096, PROT_READ) = 0
munmap(0x7fffeec80000, 13336)           = 0
openat(AT_FDCWD, "/etc/hosts", O_RDONLY|O_CLOEXEC) = 4
lseek(4, 0, SEEK_CUR)                   = 0
fstat(4, {st_mode=S_IFREG|0644, st_size=210, ...}) = 0
read(4, "# host file\n127.0.0.1    localho"..., 512) = 210
lseek(4, 0, SEEK_CUR)                   = 210
read(4, "", 512)                        = 0
close(4)                                = 0
openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 4
fstat(4, {st_mode=S_IFREG|0644, st_size=13336, ...}) = 0
mmap(NULL, 13336, PROT_READ, MAP_PRIVATE, 4, 0) = 0x7fffeec60000
close(4)                                = 0
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libnss_dns.so.2", O_RDONLY|O_CLOEXEC) = 4
read(4, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0 #\0\0\0\0\0\0"..., 832) = 832
fstat(4, {st_mode=S_IFREG|0644, st_size=31176, ...}) = 0
mmap(NULL, 32984, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 4, 0) = 0x7fffeec50000
mmap(0x7fffeec52000, 16384, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0x2000) = 0x7fffeec52000
mmap(0x7fffeec56000, 4096, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0x6000) = 0x7fffeec56000
mmap(0x7fffeec57000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0x6000) = 0x7fffeec57000
close(4)                                = 0
mprotect(0x7fffeec57000, 4096, PROT_READ) = 0
munmap(0x7fffeec60000, 13336)           = 0
socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_IP) = 4
setsockopt(4, SOL_IP, IP_RECVERR, [1], 4) = 0
connect(4, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("10.23.10.1")}, 16) = 0
poll([{fd=4, events=POLLOUT}], 1, 0)    = 1 ([{fd=4, revents=POLLOUT}])
sendto(4, "\211\350\1\0\0\1\0\0\0\0\0\0\10blackdot\2be\0\0\34\0\1", 29, MSG_NOSIGNAL, NULL, 0) = 29
poll([{fd=4, events=POLLIN}], 1, 5000)  = 1 ([{fd=4, revents=POLLIN}])
ioctl(4, FIONREAD, [57])                = 0
recvfrom(4, "\211\350\201\200\0\1\0\1\0\0\0\0\10blackdot\2be\0\0\34\0\1\300\f\0"..., 1024, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("10.23.10.1")}, [28->16]) = 57
close(4)                                = 0
socket(AF_INET6, SOCK_DGRAM, IPPROTO_IP) = 4
connect(4, {sa_family=AF_INET6, sin6_port=htons(1025), sin6_flowinfo=htonl(0), inet_pton(AF_INET6, "2001:41d0:2:bd6b::100", &sin6_addr), sin6_scope_id=0}, 28) = 0
getsockname(4, {sa_family=AF_INET6, sin6_port=htons(33483), sin6_flowinfo=htonl(0), inet_pton(AF_INET6, "2a02:578:470f:10::140", &sin6_addr), sin6_scope_id=0}, [28]) = 0
close(4)                                = 0
setsockopt(3, SOL_IPV6, IPV6_RECVERR, [1], 4) = -1 ENOPROTOOPT (Protocol not available)
write(2, "ping6: ", 7ping6: )                  = 7
write(2, "IPV6_RECVERR", 12IPV6_RECVERR)            = 12
openat(AT_FDCWD, "/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 4
fstat(4, {st_mode=S_IFREG|0644, st_size=2996, ...}) = 0
read(4, "# Locale name alias data base.\n#"..., 3072) = 2996
read(4, "", 3072)                       = 0
close(4)                                = 0
openat(AT_FDCWD, "/usr/share/locale/en_US.UTF8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en_US.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en.UTF8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale-langpack/en_US.UTF8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale-langpack/en_US.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale-langpack/en_US/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale-langpack/en.UTF8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale-langpack/en.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale-langpack/en/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
write(2, ": Protocol not available", 24: Protocol not available) = 24
write(2, "\n", 1
)                       = 1
close(1)                                = 0
close(2)                                = 0
exit_group(2 <unfinished ...>
+++ exited with 2 +++

setsockopt(3, SOL_IPV6, IPV6_RECVERR, [1], 4) = -1 ENOPROTOOPT (Protocol not available)

Probably this socket option