Page History

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For each ping sent to www.cern.ch from pinger.slac.stanford.edu or ping.desy.de, perfsonar-unimas.myren.net.my (but  not from pinger-host.fnal.gov, netmon.physics.carleton.ca) it responds with ~3 pings consistently. Using the normal traceroute www.cern.ch from SLAC does not respond. Using the ICMP traceroute it does respond (twice). Pinging each node along the route using pingroute.pl (http:/http://www-dev.slac.stanford.edu/cgi-wrap/scriptdoc.pl?name=pingroute.pl) (unfortunately mtr does not report duplicates), it is seen that only www.cern.ch responds with duplicate packets. Also looking at the tcpdump output is is seen that only one IP address is responding.

A possible source is the Load Balancing of the CERN www server. SLAC also load balances (via F5s) its www server. However, the SLAC Load Balancer only forwards the http/https requests to the web servers, the pings are responded to bet by the F5 load balancer itself.  Thus though we pinged www.slac.stanford.edu from ping.desy.de, we do not see any duplicate pings.

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• The current number of countries with remote hosts being monitored is  171.
• The number of remote hosts being monitored in 2014 is 836.
• Of these, 81 recorded 1 or more lines (samples) with duplicate pings.

• Of the 128 S. E. Asian hosts monitored from SLAC (number of hosts with DUPs / number of hosts monitored in country)

  BN	IN	KH	LA	MM	MY	PH	SG	TH	VN
  0/5	1/50	0/1	1.4	0/3	0/40	0/10	0/7	1/11	1/4

• The major contributor since 2006 has been www.cern.ch, each year we see about 60 different hosts responding with DUPs.
• A list of the hosts responding with DUP pings in 2014 is below, followed by a summary of the annual DUP pings.

List of hosts responding with DUPlicate pings as seen from SLAC in 2014

• 2014: cbinet.bi seen duping 35 times
• 2014: internet.fo seen duping 6 times
• 2014: ms01.linea.gov.br seen duping 1 times
• 2014: ns.conacyt.gob.sv seen duping 3 times
• 2014: ping.cern.ch seen duping 450 times
• 2014: pinger.daffodilvarsity.edu.bd seen duping 2 times
• 2014: pinger.ictp.it seen duping 1 times
• 2014: pinger.numl.edu.pk seen duping 96 times
• 2014: pingerqta.pern.edu.pk seen duping 1 times
• 2014: www.acgrc.am seen duping 2 times
• 2014: www.afribone.net.gn seen duping 2 times
• 2014: www.afrinet.cd seen duping 8 times
• 2014: www.aic.ac.nz seen duping 1 times
• 2014: www.alard.ps seen duping 1 times
• 2014: www.bonesha.bi seen duping 73 times
• 2014: www.boz.zm seen duping 4 times
• 2014: www.cern.ch seen duping 14026 times
• 2014: www.cnrst.bf seen duping 43 times
• 2014: www.cyfronet.krakow.pl seen duping 1 times
• 2014: www.drtvnet.cg seen duping 12 times
• 2014: www.eritel.com.er seen duping 373 times
• 2014: www.gov.bw seen duping 635 times
• 2014: www.granma.cu seen duping 9 times
• 2014: www.hraparak.am seen duping 1 times
• 2014: www.ihep.su seen duping 1 times
• 2014: www.kcn.unima.mw seen duping 118 times
• 2014: www.lanl.gov seen duping 1 times
• 2014: www.lonab.bf seen duping 394 times
• 2014: www.lsx.com.la seen duping 1 times
• 2014: www.minzdrav.uz seen duping 12 times
• 2014: www.ml.refer.org seen duping 1 times
• 2014: www.nomad.mu seen duping 1 times
• 2014: www.rmutsv.ac.th seen duping 4 times
• 2014: www.rub.edu.bt seen duping 1 times
• 2014: www.stmaryuniversitycollege.edu.et seen duping 1 times
• 2014: www.uniswafoundation.org.sz seen duping 1 times
• 2014: www.univ-koudougou.bf seen duping 632 times
• 2014: www.univ-ouaga.bf seen duping 7 times
• 2014: www.uns.ac.id seen duping 2 times
• 2014: www.vnu.edu.vn seen duping 26 times
• 2014: www.vnuhcm.edu.vn seen duping 1 times

 Summary of yearly data of DUP pings seen from SLAC

See spreadsheet.

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