[LINK] Webserver unavailability patterns

[David Lochrin]

At 08:22 AM 03-10-2002 +1000, Jan Whitaker wrote:
>Have any other linkers noticed an increase in unavailable websites?  Just 
>now I've been trying to do a bpay and the westpac site stopped 
>responding.  Then to see if it was just them, I tried ABC.net.au/news - 
>also not responding. Then I tried another .au site and it came up just 
>fine, as did a US based .com site.  I've even closed and reopened the 
>browser to be sure it wasn't hung up.

   Very interesting!

   Quite some time ago I found that the National Library  http://www.nla.gov.au  became unavailable.  A recent email to NOIE, who I believe host NLA, elicited the helpful response "It works for me.  Why don't you try again?"

   Recently I noticed ASIC  http://www.asic.gov.au  had disappeared, and a few weeks ago I found the Australian Catholic University  http://www.acu.edu.au  had gone over the horizon.

   This resulted in a call to my ISP, Dot Communications, and some diagnostic work by moi.  If I attempt to access www.nla.gov.au from the browser and then run  'netstat -r  www.nla.gov.au' from a DOS window, the part of the display showing active TCP connections shows an outbound connection to  'www-prod.nla.gov.au:80' in state 'SYN_SENT' which indicates the browser has successfully resolved the server name and initiated a TCP connection to port 80, but hasn't received a TCP response.  However if I configure the browser to use Dot's proxy server instead of a "direct connection to the Internet" everything works just fine.

   I'm using the Netscape V4.77 browser, but Mozilla V1.1 shows the same results.  Forcing the browser to use the HTTP secondary port '8080' doesn't change anything (as one would hope!).

   You might also try using TRACEROUTE from a DOS window, for example  'tracert www.nla.gov.au'   A working site will respond like this:

C:\WINDOWS>tracert sunsite.anu.edu.au

Tracing route to boomer.anu.edu.au [150.203.99.2]
over a maximum of 30 hops:

  1   144 ms   130 ms   127 ms  acc02-kent-syd.comindico.com.au [203.194.30.2]
  2   129 ms   124 ms   128 ms  203.194.60.254
  3   131 ms   125 ms   121 ms  ge6-1.cor01-syd.comindico.com.au [203.194.28.233]
  4   330 ms   281 ms   266 ms  ge5-0-0.bdr01-kent-syd.comindico.com.au [203.194.29.242]
  5   128 ms   125 ms   124 ms  ATM-4-0-0-1.sn2.optus.net.au [203.202.186.173]
  6   151 ms   143 ms   145 ms  Gi5-0.cn1.optus.net.au [202.139.191.130]
  7   148 ms   147 ms   147 ms  ACT-RNO-Dom.cn1.optus.net.au [202.139.39.246]
  8   151 ms   146 ms   147 ms  anu-huxley.carno.net.au [203.22.212.66]
  9   156 ms   157 ms   153 ms  boomer.anu.edu.au [150.203.99.2]

Trace complete.

C:\WINDOWS>

   I'd be really interested to hear the results, as Dot seem to have dropped the ball.  I suspect a problem in the underlying network.

David Lochrin

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David Lochrin
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