Eu tenho um problema de ping estranho, após uma atualização do Ubuntu 12.04. para 14.04.
Eu não posso ping com o nome do host, mas com o ip funciona. Eu não tenho quaisquer outros problemas de DNS com outros serviços ou programas.
Eu trabalho como usuário normal, mas não como root.
Como host de usuário root e escavação pode resolver o dnsname para um ip.
O ping do busybox também funciona com o nome do host.
Este é o erro:
root@myhost:~# ping ubuntu.com
ping: unknown host ubuntu.com
Isso funciona:
root@myhost:~# host ubuntu.com
ubuntu.com has address 91.189.94.40
ubuntu.com mail is handled by 10 mx.canonical.com.
root@myhost:~# ping 91.189.94.40 -c 1
PING 91.189.94.40 (91.189.94.40) 56(84) bytes of data.
64 bytes from 91.189.94.40: icmp_seq=1 ttl=53 time=16.1 ms
root@myhost:~# busybox ping ubuntu.com -c 1
PING ubuntu.com (91.189.94.40): 56 data bytes
64 bytes from 91.189.94.40: seq=0 ttl=53 time=16.189 ms
user@myhost:~$ ping ubuntu.com -c 1
PING ubuntu.com (91.189.94.40) 56(84) bytes of data.
64 bytes from ovinnik.canonical.com (91.189.94.40): icmp_seq=1 ttl=53 time=16.1 ms
arquivo /etc/nsswitch.conf
root@myhost:~# cat /etc/nsswitch.conf
# /etc/nsswitch.conf
#
# Example configuration of GNU Name Service Switch functionality.
# If you have the 'glibc-doc-reference' and 'info' packages installed, try:
# 'info libc "Name Service Switch"' for information about this file.
passwd: compat
group: compat
shadow: compat
hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4
networks: files
protocols: db files
services: db files
ethers: db files
rpc: db files
netgroup: nis
algumas informações adicionais. obrigado pela dica strace. appamor não está ativo.
strace: parece ser problema para abrir /etc/resolv.conf, mas menos como root funciona
root@myhost:~# strace -e open ping -c 1 ubuntu.com
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libcap.so.2", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
open("/etc/resolv.conf", O_RDONLY|O_CLOEXEC) = -1 EACCES (Permission denied)
open("/etc/nsswitch.conf", O_RDONLY|O_CLOEXEC) = -1 EACCES (Permission denied)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = -1 EACCES (Permission denied)
open("/lib/x86_64-linux-gnu/tls/x86_64/libnss_dns.so.2", O_RDONLY|O_CLOEXEC) = -1 EACCES (Permission denied)
open("/lib/x86_64-linux-gnu/tls/libnss_dns.so.2", O_RDONLY|O_CLOEXEC) = -1 EACCES (Permission denied)
open("/lib/x86_64-linux-gnu/x86_64/libnss_dns.so.2", O_RDONLY|O_CLOEXEC) = -1 EACCES (Permission denied)
open("/lib/x86_64-linux-gnu/libnss_dns.so.2", O_RDONLY|O_CLOEXEC) = -1 EACCES (Permission denied)
open("/usr/lib/x86_64-linux-gnu/tls/x86_64/libnss_dns.so.2", O_RDONLY|O_CLOEXEC) = -1 EACCES (Permission denied)
open("/usr/lib/x86_64-linux-gnu/tls/libnss_dns.so.2", O_RDONLY|O_CLOEXEC) = -1 EACCES (Permission denied)
open("/usr/lib/x86_64-linux-gnu/x86_64/libnss_dns.so.2", O_RDONLY|O_CLOEXEC) = -1 EACCES (Permission denied)
open("/usr/lib/x86_64-linux-gnu/libnss_dns.so.2", O_RDONLY|O_CLOEXEC) = -1 EACCES (Permission denied)
open("/lib/tls/x86_64/libnss_dns.so.2", O_RDONLY|O_CLOEXEC) = -1 EACCES (Permission denied)
open("/lib/tls/libnss_dns.so.2", O_RDONLY|O_CLOEXEC) = -1 EACCES (Permission denied)
open("/lib/x86_64/libnss_dns.so.2", O_RDONLY|O_CLOEXEC) = -1 EACCES (Permission denied)
open("/lib/libnss_dns.so.2", O_RDONLY|O_CLOEXEC) = -1 EACCES (Permission denied)
open("/usr/lib/tls/x86_64/libnss_dns.so.2", O_RDONLY|O_CLOEXEC) = -1 EACCES (Permission denied)
open("/usr/lib/tls/libnss_dns.so.2", O_RDONLY|O_CLOEXEC) = -1 EACCES (Permission denied)
open("/usr/lib/x86_64/libnss_dns.so.2", O_RDONLY|O_CLOEXEC) = -1 EACCES (Permission denied)
open("/usr/lib/libnss_dns.so.2", O_RDONLY|O_CLOEXEC) = -1 EACCES (Permission denied)
ping: unknown host ubuntu.com
+++ exited with 2 +++
getent:
root @ myhost: ~ # hosts de recepção ubuntu.com
91.189.94.40 ubuntu.com
getcap:
root@myhost:~# getcap -rv /bin/ping
/bin/ping
permissões:
root@myhost:/etc# ls -lha /etc/resolv.conf
lrwxrwxrwx 1 root root 29 Jan 9 11:11 /etc/resolv.conf -> ../run/resolvconf/resolv.conf
root@myhost:/etc# ls -lha /run/resolvconf/resolv.conf
-rw-r--r-- 1 root root 237 Jan 10 08:52 /run/resolvconf/resolv.conf
root@myhost:/etc# ls -lha /etc/hosts
-rw-r--r-- 1 root root 485 Jan 8 09:15 /etc/hosts
root@myhost:/etc# ls -lha /etc/nsswitch.conf
-rw-r--r-- 1 root root 513 Jan 8 09:08 /etc/nsswitch.conf
resolv.conf: (o mesmo que em outro host, se funciona)
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 213.133.98.98
nameserver 213.133.99.99
nameserver 213.133.100.100