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Thread: Crazy strange network issue where HTTP request hangs

  1. #1
    Join Date
    Oct 2012
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    2

    Exclamation Crazy strange network issue where HTTP request hangs

    Hi all,

    Have a really strange problem which has been driving me crazy. When I try to resolve a domain it hangs. I've tested with both wget and curl (result pasted below - notice the 49:17 request time without response, yes, that's 50 minutes!), just in case it was a browser issue (tested with Firefox, Chrome, Opera and SeaMonkey), but the same happens from shell. Pinging the URL works because I assume the first node resolves, it just hangs on the second forwarded location.

    But wait, here's the "real" issue: It ONLY happens until now with http://www.google.com (please bare with me). I have 2 other laptops with the same OS (Ubuntu 11.04), and they work perfect. NO ISSUE. Am I losing my mind? Could this possibly be malware?

    Thank you in advance to anyone who can help.


    $ uname -a
    Linux homedev 2.6.38-16-generic #67-Ubuntu SMP Thu Sep 6 17:58:38 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux


    $ ifconfig
    eth0 Link encap:Ethernet HWaddr 78:ac:c0:5b:4a:6d
    UP BROADCAST MULTICAST MTU:1500 Metric:1
    RX packets:0 errors:0 dropped:0 overruns:0 frame:0
    TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
    collisions:0 txqueuelen:1000
    RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
    Interrupt:11 Base address:0x4000

    lo Link encap:Local Loopback
    inet addr:127.0.0.1 Mask:255.0.0.0
    inet6 addr: ::1/128 Scope:Host
    UP LOOPBACK RUNNING MTU:16436 Metric:1
    RX packets:1495 errors:0 dropped:0 overruns:0 frame:0
    TX packets:1495 errors:0 dropped:0 overruns:0 carrier:0
    collisions:0 txqueuelen:0
    RX bytes:201227 (201.2 KB) TX bytes:201227 (201.2 KB)

    wlan0 Link encap:Ethernet HWaddr 1c:65:9d:e2:6b:f2
    inet addr:192.168.1.128 Bcast:192.168.1.255 Mask:255.255.255.0
    inet6 addr: fe80::1e65:9dff:fee2:6bf2/64 Scope:Link
    UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
    RX packets:83519 errors:0 dropped:0 overruns:0 frame:0
    TX packets:125590 errors:0 dropped:0 overruns:0 carrier:0
    collisions:0 txqueuelen:1000
    RX bytes:23481536 (23.4 MB) TX bytes:149335230 (149.3 MB)
    Interrupt:11 Memory:ffffc900050c0000-ffffc900050c0100


    $ curl --location --verbose google.com
    * About to connect() to google.com port 80 (#0)
    * Trying 173.194.34.201... % Total % Received % Xferd Average Speed Time Time Time Current
    Dload Upload Total Spent Left Speed
    0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0connected
    * Connected to google.com (173.194.34.201) port 80 (#0)
    > GET / HTTP/1.1
    > User-Agent: curl/7.21.3 (x86_64-pc-linux-gnu) libcurl/7.21.3 OpenSSL/0.9.8o zlib/1.2.3.4 libidn/1.18
    > Host: google.com
    > Accept: */*
    >
    < HTTP/1.1 301 Moved Permanently
    < Location: http://www.google.com/
    < Content-Type: text/html; charset=UTF-8
    < Date: Thu, 04 Oct 2012 17:50:23 GMT
    < Expires: Sat, 03 Nov 2012 17:50:23 GMT
    < Cache-Control: public, max-age=2592000
    < Server: gws
    < Content-Length: 219
    < X-XSS-Protection: 1; mode=block
    < X-Frame-Options: SAMEORIGIN
    <
    * Ignoring the response-body
    { [data not shown]
    100 219 100 219 0 0 1175 0 --:--:-- --:--:-- --:--:-- 3590* Connection #0 to host google.com left intact
    * Issue another request to this URL: 'http://www.google.com/'
    * About to connect() to www.google.com port 80 (#1)
    * Trying 212.106.221.23... connected
    * Connected to www.google.com (212.106.221.23) port 80 (#1)
    > GET / HTTP/1.1
    > User-Agent: curl/7.21.3 (x86_64-pc-linux-gnu) libcurl/7.21.3 OpenSSL/0.9.8o zlib/1.2.3.4 libidn/1.18
    > Host: www.google.com
    > Accept: */*
    >
    0 219 0 0 0 0 0 0 --:--:-- 0:49:17 --:--:-- 0


    $ ping google.com
    PING google.com (173.194.34.206) 56(84) bytes of data.
    64 bytes from mad01s08-in-f14.1e100.net (173.194.34.206): icmp_req=1 ttl=56 time=111 ms
    64 bytes from mad01s08-in-f14.1e100.net (173.194.34.206): icmp_req=2 ttl=56 time=36.9 ms
    64 bytes from mad01s08-in-f14.1e100.net (173.194.34.206): icmp_req=3 ttl=56 time=78.3 ms
    64 bytes from mad01s08-in-f14.1e100.net (173.194.34.206): icmp_req=4 ttl=56 time=98.9 ms
    ^C
    --- google.com ping statistics ---
    4 packets transmitted, 4 received, 0% packet loss, time 3003ms
    rtt min/avg/max/mdev = 36.961/81.428/111.546/28.283 ms


    $ traceroute google.com
    traceroute to google.com (173.194.34.200), 30 hops max, 60 byte packets
    1 192.168.1.1 (192.168.1.1) 1.924 ms 2.024 ms 3.467 ms
    2 1.224.222.87.dynamic.jazztel.es (87.222.224.1) 35.101 ms 35.456 ms 36.146 ms
    3 10.255.5.254 (10.255.5.254) 64.945 ms 68.373 ms 68.416 ms
    4 102.217.106.212.static.jazztel.es (212.106.217.102) 44.825 ms 110.217.106.212.static.jazztel.es (212.106.217.110) 45.824 ms 102.217.106.212.static.jazztel.es (212.106.217.102) 45.786 ms
    5 109.217.106.212.static.jazztel.es (212.106.217.109) 44.671 ms 45.863 ms 45.794 ms
    6 254.216.106.212.static.jazztel.es (212.106.216.254) 53.943 ms 35.877 ms 36.087 ms
    7 2.217.106.212.static.jazztel.es (212.106.217.2) 34.672 ms 35.079 ms 35.053 ms
    8 216.239.49.196 (216.239.49.196) 36.728 ms 36.102 ms 36.662 ms
    9 72.14.237.124 (72.14.237.124) 38.013 ms 37.379 ms 38.274 ms
    10 mad01s08-in-f8.1e100.net (173.194.34.200) 37.606 ms 38.579 ms 39.164 ms

  2. #2
    Join Date
    Oct 2012
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    7

    Lightbulb Re: Crazy strange network issue where HTTP request hangs

    I am new to Ubuntu (And other than Android, Linux period) but I would guess your Internet connection is not configured properly. Or you may need to reinstall Ubuntu on that computer, maybe that would fix it.

  3. #3
    Join Date
    Jul 2012
    Beans
    58

    Re: Crazy strange network issue where HTTP request hangs

    Since there is some unknown link inside the google.com page that is hanging, then that is probably just a DNS issue for that particular domain name in that link.

    A reason that not all of your PCs have this problem could be that the DNS cache has already expired on the failing PC. So this is the only one PC (out of your 3) that needs to resolve the domain name. If the domain name is not resolvable right now, then it fails even as the other PCs with a cached entry still reach the IP of that domain name.

    In other words, you don't need malware to have this problem.

  4. #4
    Join Date
    Oct 2012
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    Question Re: Crazy strange network issue where HTTP request hangs

    Quote Originally Posted by mevun View Post
    Since there is some unknown link inside the google.com page that is hanging, then that is probably just a DNS issue for that particular domain name in that link.

    A reason that not all of your PCs have this problem could be that the DNS cache has already expired on the failing PC. So this is the only one PC (out of your 3) that needs to resolve the domain name. If the domain name is not resolvable right now, then it fails even as the other PCs with a cached entry still reach the IP of that domain name.

    In other words, you don't need malware to have this problem.
    Thanks for the prompt reply mevun. The strange thing is, that when loading the domain in a browser it displays correctly (shows the Google logo with the search box), but any subsequent request (i.e: searching), the request hangs. So, it works for the first request, but fails after that, as demonstrated with curl in my example.

    The only way to get it to resolve again is to RESET my internet connection - in Ubuntu, from the network icon in the taskbar (gnome2) clicking the icon of my active WiFi connection in the popup menu to reconnect - then it magically works again. That's an important fact I'm not sure if I stated in my post: I'm using a WiFi connection, not cable.

  5. #5
    Join Date
    Jul 2012
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    58

    Re: Crazy strange network issue where HTTP request hangs

    Quote Originally Posted by kanedase7en View Post
    Thanks for the prompt reply mevun. The strange thing is, that when loading the domain in a browser it displays correctly (shows the Google logo with the search box), but any subsequent request (i.e: searching), the request hangs. So, it works for the first request, but fails after that, as demonstrated with curl in my example.

    The only way to get it to resolve again is to RESET my internet connection - in Ubuntu, from the network icon in the taskbar (gnome2) clicking the icon of my active WiFi connection in the popup menu to reconnect - then it magically works again. That's an important fact I'm not sure if I stated in my post: I'm using a WiFi connection, not cable.
    I don't know much about WiFi, but I agree then that it isn't a DNS caching problem that I described. I have read that Firefox has its own DNS cache; don't know if it can become corrupt or how/why resetting a wifi connection would help.

    Anyway, I still doubt the cause is malware since I thought that is fairly rare for Linux, but I don't know how you can further debug this problem either.

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