Chrome and Safari can browse the internet, but ping and other command-line tools can't

Question

I'm using Mac OS X 10.6, and the problem appeared after the latest update.

Chrome and Safari can browse the Internet fine, but I can't ping google.com or apple.com. I have also found that bzr fails, but git works for some reason.

I thought it might be an IPv6 issue, so I tried disabling IPv6 on all the interfaces I could, but the problem continued.

I have no idea what might be causing this. Thanks for any help you can give!

Edit:

ifconfig produces

lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
    inet6 ::1 prefixlen 128 
    inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1 
    inet 127.0.0.1 netmask 0xff000000 
gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280
stf0: flags=0<> mtu 1280
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
    ether 00:25:00:a9:93:9e 
    inet6 fe80::225:ff:fea9:939e%en0 prefixlen 64 scopeid 0x4 
    inet 165.82.76.128 netmask 0xffffff00 broadcast 165.82.76.255
    media: autoselect (100baseTX <full-duplex>)
    status: active
fw0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 4078
    lladdr 00:25:00:ff:fe:a9:93:9e 
    media: autoselect <full-duplex>
    status: inactive
en1: flags=8823<UP,BROADCAST,SMART,SIMPLEX,MULTICAST> mtu 1500
    ether 00:24:36:af:45:d4 
    media: autoselect (<unknown type>)
    status: inactive
en2: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
    ether 00:1c:42:00:00:08 
    inet6 fe80::21c:42ff:fe00:8%en2 prefixlen 64 scopeid 0x7 
    inet 10.211.55.2 netmask 0xffffff00 broadcast 10.211.55.255
    media: autoselect
    status: active
en3: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
    ether 00:1c:42:00:00:09 
    inet6 fe80::21c:42ff:fe00:9%en3 prefixlen 64 scopeid 0x8 
    inet 10.37.129.2 netmask 0xffffff00 broadcast 10.37.129.255
    media: autoselect
    status: active

And ipfw list produces

65535 allow ip from any to any

Answer 1

Can you ping your Gateway or any PC on the same LAN? May be it's just that your school disable ping going out of school network. Networks with lot of users usually block ICMP traffic from going out/getting into their network for security reason. Same for my university here. (Ping use ICMP protocal).

Answer 2

Noah: are you connected to a vpn? What's with the en2 and en3 interfaces?

It looks like you have one outward facing ip address on en0, and 2 private IP addresses on en2 and en3 (i assume en1 is airport and it's set to off).

Try disabling en2 and en3 and see if your command line troubles go away. There's a lot of unanswered questions here, but I wonder if you're using a proxy through a vpn for your web surfing...