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qdii
Tux's lil' helper
Joined: 19 Sep 2009
Posts: 106
Location: Madrid
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 Posted: Sun Nov 27, 2011 1:56 am Post subject: Can’t ping a given ip address, ping hangs |
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Hey,
I have 2 computers which are both connected to the same wifi router. They can both ping websites such as www.wikipedia.org or www.google.com, and can ping each other too, but one of them can ping 188.165.195.37, and the other one can’t. When I say it can’t ping, I mean ping hangs till I kill it.
Both computers have the same route table: http://paste.pocoo.org/show/513378/
I am getting more and more confused
Last edited by qdii on Sun Nov 27, 2011 2:29 pm; edited 1 time in total |
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Hu
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Joined: 06 Mar 2007
Posts: 23121
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| Posted: Sun Nov 27, 2011 2:03 am Post subject: |
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| What if you use ping -c4 188.165.195.37? |
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qdii
Tux's lil' helper
Joined: 19 Sep 2009
Posts: 106
Location: Madrid
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| Posted: Sun Nov 27, 2011 2:05 am Post subject: |
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So what I did was running strace ping on the computer that cannot ping, I ended up with that:
http://paste.pocoo.org/show/513387
| Code: |
recvmsg(3, 0x7fffbb30c670, 0) = -1 EAGAIN (Resource temporarily unavailable)
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That line is very surprising, I wonder how that could happen…
EDIT: dug further, the documentation here states that:
| Quote: | [EAGAIN] or [EWOULDBLOCK]
The socket's file descriptor is marked O_NONBLOCK and no data is waiting to be received; or MSG_OOB is set and no out-of-band data is available and either the socket's file descriptor is marked O_NONBLOCK or the socket does not support blocking to await out-of-band data. |
That’s not our case since the third flag is 0, and O_NONBLOCK is defined to be 0x4, 0x80, 0x4000 or 0x200004 depending on the architecture. MSG_OOB is defined to 1. So this looks pretty weird now.
Last edited by qdii on Sun Nov 27, 2011 12:55 pm; edited 1 time in total |
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qdii
Tux's lil' helper
Joined: 19 Sep 2009
Posts: 106
Location: Madrid
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| Posted: Sun Nov 27, 2011 2:06 am Post subject: |
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| Hu: doesn’t get better with -c4 |
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Hu
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| Posted: Sun Nov 27, 2011 5:19 am Post subject: |
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| qdii wrote: | | Hu: doesn’t get better with -c4 |
You mean that ping never exits, even with -c4? |
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qdii
Tux's lil' helper
Joined: 19 Sep 2009
Posts: 106
Location: Madrid
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| Posted: Sun Nov 27, 2011 11:58 am Post subject: |
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| Sorry, yes it exits with "100% packet loss" when I set -c4 |
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qdii
Tux's lil' helper
Joined: 19 Sep 2009
Posts: 106
Location: Madrid
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| Posted: Sun Nov 27, 2011 12:18 pm Post subject: |
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| I’ve made a little step forward: the same problem strikes up when I connect through an ethernet cable. |
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Hu
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Posts: 23121
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| Posted: Sun Nov 27, 2011 6:06 pm Post subject: |
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| What is the output of traceroute -I -n 188.165.195.37, as run by both the successful and failed systems? |
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qdii
Tux's lil' helper
Joined: 19 Sep 2009
Posts: 106
Location: Madrid
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| Posted: Mon Nov 28, 2011 9:59 am Post subject: |
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Hey,
thanks for your help. Everything eventually turned out fine after I reseted the router settings.
No idea what was going wrong |
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