Internet sobre Ethernet: o DNS funciona, ping não (o Windows funciona, o Linux não)

4

Eu tenho um PC conectado à Internet usando uma conexão Ethernet. Usando o Ubuntu eu consigo resolver domínios usando nslookup, mas se eu tentar rodar "ping google.com" ou "ping 74.125.39.104" ele não funciona.

Eu usei Arch Linux, Mint e Ubuntu Live em dois netbooks, todos sem sucesso. O Windows, no entanto, funciona bem. Salve-me de usar o Windows!

ifconfig:

sudo ifconfig eth0
eth0      Link encap:Ethernet  HWaddr 00:26:18:80:79:18  
          inet addr:10.20.6.180  Bcast:10.20.7.255  Mask:255.255.254.0
          inet6 addr: fe80::226:18ff:fe80:7918/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:5751 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2397 errors:0 dropped:0 overruns:0 carrier:17
          collisions:0 txqueuelen:1000 
          RX bytes:659976 (659.9 KB)  TX bytes:253881 (253.8 KB)
          Interrupt:40

route:

route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
10.20.6.0       0.0.0.0         255.255.254.0   U     1      0        0 eth0
169.254.0.0     0.0.0.0         255.255.0.0     U     1000   0        0 eth0
0.0.0.0         10.20.6.1       0.0.0.0         UG    0      0        0 eth0
0.0.0.0         10.20.6.1       0.0.0.0         UG    202    0        0 eth0

netstat:

netstat -nr
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
10.20.6.0       0.0.0.0         255.255.254.0   U         0 0          0 eth0
169.254.0.0     0.0.0.0         255.255.0.0     U         0 0          0 eth0
0.0.0.0         10.20.6.1       0.0.0.0         UG        0 0          0 eth0
0.0.0.0         10.20.6.1       0.0.0.0         UG        0 0          0 eth0

iptables:

sudo iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

resolv.conf:

cat /etc/resolv.conf
# Generated by resolvconf 
search uni-mannheim.de 
nameserver 134.155.96.51 
nameserver 134.155.96.53

o tracepath não está funcionando:

sudo tracepath www.google.com
 1:  laptop.local                                          0.342ms pmtu 1500
 1:  no reply
 2:  no reply
 3:  no reply
 4:  no reply

/etc/host.conf

sudo cat /etc/host.conf
# The "order" line is only used by old versions of the C library.
order hosts,bind
multi on

/etc/nsswitch.conf

sudo 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

nslookup google.com

nslookup google.com
Server:     134.155.96.51
Address:    134.155.96.51#53

Non-authoritative answer:
Name:   google.com
Address: 74.125.39.104
Name:   google.com
Address: 74.125.39.105
Name:   google.com
Address: 74.125.39.106
Name:   google.com
Address: 74.125.39.147
Name:   google.com
Address: 74.125.39.99
Name:   google.com
Address: 74.125.39.103

wget google.com

wget google.com
--2011-08-17 11:05:01--  http://google.com/
Resolving google.com... 74.125.39.99, 74.125.39.103, 74.125.39.104, ...
Connecting to google.com|74.125.39.99|:80...

digitam o google.com

o tracepath não funciona, mas o dig faz

dig google.com

; <<>> DiG 9.7.3 <<>> google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 2643
;; flags: qr rd ra; QUERY: 1, ANSWER: 6, AUTHORITY: 4, ADDITIONAL: 4

;; QUESTION SECTION:
;google.com.            IN  A

;; ANSWER SECTION:
google.com.     175 IN  A   74.125.39.103
google.com.     175 IN  A   74.125.39.104
google.com.     175 IN  A   74.125.39.105
google.com.     175 IN  A   74.125.39.106
google.com.     175 IN  A   74.125.39.147
google.com.     175 IN  A   74.125.39.99

;; AUTHORITY SECTION:
google.com.     104161  IN  NS  ns4.google.com.
google.com.     104161  IN  NS  ns3.google.com.
google.com.     104161  IN  NS  ns1.google.com.
google.com.     104161  IN  NS  ns2.google.com.

;; ADDITIONAL SECTION:
ns1.google.com.     277325  IN  A   216.239.32.10
ns2.google.com.     277325  IN  A   216.239.34.10
ns3.google.com.     277325  IN  A   216.239.36.10
ns4.google.com.     277325  IN  A   216.239.38.10

;; Query time: 2 msec
;; SERVER: 134.155.96.51#53(134.155.96.51)
;; WHEN: Wed Aug 17 11:06:14 2011
;; MSG SIZE  rcvd: 260
    
por Francesco 16.08.2011 / 10:58

3 respostas

1

Não se preocupe muito com o ping, não é incomum que o ping seja bloqueado pela infraestrutura do servidor. Ping e traceroute geralmente usam ICMP. Um teste melhor é usar wget http://www.google.com , que usa HTTP.

Primeiro, use host www.google.com para testar o DNS (sistemas Linux mais antigos teriam nslookup ou dig em vez de host )

$ host www.google.com
www.google.com is an alias for www.l.google.com.
www.l.google.com has address 209.85.143.104
www.l.google.com has address 209.85.143.99


$ wget http://www.google.com
--12:21:13--  http://www.google.com/
           => 'index.html'
Resolving www.google.com... done.
Connecting to www.google.com[209.85.143.99]:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [text/html]

    [                                  ] 9,931        167.21K/s

12:21:14 (167.21 KB/s) - 'index.html' saved [9931]
    
por 16.08.2011 / 13:23
0

Qual é o seu /etc/resolve.conf? Deve apontar para o seu roteador

Este arquivo é muito importante para se conectar à internet.

    
por 16.08.2011 / 11:27
0

Verifique o firewall Firestarter:

chkconfig -l | grep firestarter

firestarter 0:off 1:off 2:off 3:off 4:off 5:off 6:off S:on

Desativar o firewall Firestarter:

sudo chkconfig firestarter off

e verifique novamente:

chkconfig -l | grep firestarter

firestarter 0:off 1:off 2:off 3:off 4:off 5:off 6:off

e pare o firewall:

sudo firestarter -p

Continue, tente fazer o ping novamente.

    
por 09.05.2012 / 22:40