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I am using Ubuntu with a 2Mbps link. I would do scp to the Ubuntu cloud servers to copy a .war file which is 14MB. It used to take only 2 minutes to copy this .war file under /tmp of the cloud server. Now it takes more than 15 minutes.

While doing scp it stalls and restarts again. The scp progress looks like this:

app1.war                     15%    2320KB  61.3KB/s - stalled -^

Any tips? I'm asked to fix this soon.

The output of tcpdump -n -n host my-dest-ip and port 22 is (I just stopped it with Ctrl+C)

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
^C
0 packets captured
0 packets received by filter
0 packets dropped by kernel
chutz
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user53864
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1 Answers1

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it would be useful to find out if anything obvious is going wrong at the network level. do you have root on either end? can you do a tcpdump to isolate the scp datastream?

MadHatter
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  • Yeah root is present. I don't have any idea of how to do tcpdump – user53864 Sep 28 '10 at 14:46
  • on the source box, try "tcpdump -n -n host DESTINATION_BOX and port 22", replacing DESTINATION_BOX with the ip address of the destination box. i should add that by "do you have root" i mean "do you have root access", which you will need to do a tcpdump. – MadHatter Sep 28 '10 at 15:17
  • Sorry!. As you said `it would be useful to find out if anything obvious is going wrong at the network leve` it was my ISP's problem. – user53864 Jan 22 '11 at 02:19
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    Well, four cheers for you for coming back and letting us all know! Glad it's fixed, but if I were you, I'd spend a couple of hours learning to use tcpdump in the interim; it's an *extremely* useful tool for diagnosing problems like this (look for retransmissions, weird ICMP grumbles, that kind of thing). – MadHatter Jan 22 '11 at 07:53
  • I would like to copy your habits. I'll learn that. Thanks! – user53864 Jan 23 '11 at 16:24