[bdNOG] Fwd: Problem accessing www.bb.org.bd.
Brian Candler
brian at nsrc.org
Mon Sep 14 13:49:46 BDT 2015
On 14/09/2015 07:52, Fakrul Alam wrote:
> www.bb.org.bd <http://www.bb.org.bd> site are seriously overloaded...
>
That is one theory. However, people say that if they connect via Qubee
they get fast response.
Another theory is that there is substantial packet loss over certain
paths, causing TCP delays / retransmissions. You may be able to infer
this by taking a packet capture:
tcpdump -i eth0 -w bb.pcap -nn
and then analysing bb.pcap looking for retransmissions, e.g. by hand, or
by using tcptrace and xplot.
http://www.tcptrace.org/tcptrace-manual/manual/node12_ct.html
If it's a load problem (either server load or network load) I would
expect the issue to vary by time of day, and be noticeably better in the
middle of the night.
By the way: this is a *bank*, and this is 2015. Do you really still need
to force SSLv3 to connect to them, rather than TLS? That is totally
broken. It won't be long before web browsers disable SSLv3, because of
its known security problems.
> $ curl -o /dev/null -s -w
> %{time_connect}:%{time_starttransfer}:%{time_total}\\n --sslv3
> https://www.bb.org.bd:443
> 0.072:120.083:704.965
That is an excellent start. It would be really helpful if people could
make measurements like this from different points and at different times
of day, and for someone to collate the results. This will help to
demonstrate that there *is* really a problem, and help to pinpoint what
it is.
For comparison, here's what I get from a VM in the UK (at
bytemark.co.uk): three successive tests made on 2015-09-14 at 07:40 UTC
3.912:0.000:3.912
1.001:0.000:1.001
0.448:0.000:0.447
Given the latency from UK to Bangladesh I'd say this is understandable,
although if everything is working well I would expect the third result
to be consistently achieved, not the first result.
Regards,
Brian.
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