Pinging from around the world
A friend of mine just told me about just-ping.com, a free site that will ping any domain name or IP address that you specify from multiple locations around the world. Not sure how scientific or reliable this is, but it can give a general indication of the "reachability" of your site from different places around the globe.
Some sample results follow.
wincent.dev
location result min. rrt avg. rrt max. rrt
Vancouver, Canada Okay 85.1 85.3 85.6
Santa Clara, U.S.A. Okay 76.8 83.6 110.2
New York, U.S.A. Okay 11.8 12.1 12.6
Florida, U.S.A. Okay 37.0 37.3 37.9
Austin2, U.S.A. Okay 60.6 60.7 61.1
San Francisco, U.S.A. Okay 81.1 84.0 85.5
Austin, U.S.A. Okay 60.0 60.2 60.5
Amsterdam3, Netherlands Okay 89.4 100.1 108.9
London, United Kingdom Okay 86.3 86.8 87.3
Stockholm, Sweden Okay 106.2 109.6 112.7
Madrid, Spain Okay 111.3 111.7 112.1
Sydney, Australia Okay 219.8 220.2 221.2
Amsterdam, Netherlands Okay 93.4 96.7 97.7
Cologne, Germany Okay 101.1 101.5 101.8
Munchen, Germany Okay 101.1 101.5 101.8
Kraków, Poland Okay 125.2 125.6 125.8
Lille, France Okay 90.1 90.6 91.6
Cagliari, Italy Okay 128.0 128.3 128.6
Copenhagen, Denmark Okay 101.0 104.5 107.6
Hong Kong, China Okay 230.7 244.9 259.2
Melbourne, Australia Okay 246.8 247.4 248.5
Singapore, Singapore Okay 261.5 261.7 261.9
Amsterdam2, Netherlands Okay 89.6 99.8 109.2
Porto Alegre, Brazil Okay 153.2 159.0 161.9
Paris, France Okay 107.8 112.2 117.6
Shanghai, China Packets lost (10%) 299.7 300.6 303.4
Example of a site suffering connectivity problems
Vancouver, Canada Packets lost (70%) 65.1 65.5 65.7
San Francisco, U.S.A. Packets lost (40%) 42.6 42.8 43.0
Florida, U.S.A. Packets lost (80%) 26.0 26.1 26.2
New York, U.S.A. Packets lost (70%) 55.4 55.5 55.5
Austin2, U.S.A. Packets lost (60%) 9.6 9.7 9.8
Austin, U.S.A. Packets lost (30%) 9.6 9.7 9.8
Santa Clara, U.S.A. Packets lost (50%) 50.0 82.0 209.1
Amsterdam3, Netherlands Packets lost (40%) 129.2 129.3 129.4
Sydney, Australia Packets lost (90%) 191.9 191.9 191.9
Amsterdam2, Netherlands Packets lost (70%) 129.5 129.6 129.6
Amsterdam, Netherlands Packets lost (80%) 125.8 127.8 129.7
Madrid, Spain Packets lost (90%) 149.6 149.6 149.6
Lille, France Packets lost (30%) 137.0 138.9 142.7
Munchen, Germany Packets lost (60%) 132.0 132.1 132.3
Copenhagen, Denmark Packets lost (50%) 141.8 141.9 142.1
Hong Kong, China Packets lost (70%) 238.9 251.1 257.6
Cagliari, Italy Packets lost (40%) 179.1 186.1 205.5
Paris, France Packets lost (30%) 136.8 139.4 140.6
Singapore, Singapore Packets lost (60%) 232.3 235.3 237.1
Shanghai, China Packets lost (60%) 273.3 273.6 274.0
London, United Kingdom Packets lost (30%) 106.4 106.8 107.1
Porto Alegre, Brazil Packets lost (20%) 165.8 171.5 176.5
Stockholm, Sweden Packets lost (100%)
Cologne, Germany Packets lost (100%)
Kraków, Poland Packets lost (90%) 165.9 165.9 165.9
Melbourne, Australia Packets lost (90%) 220.3 220.3 220.3
location result min. rrt avg. rrt max. rrt
Vancouver, Canada Okay 85.1 85.3 85.6
Santa Clara, U.S.A. Okay 76.8 83.6 110.2
New York, U.S.A. Okay 11.8 12.1 12.6
Florida, U.S.A. Okay 37.0 37.3 37.9
Austin2, U.S.A. Okay 60.6 60.7 61.1
San Francisco, U.S.A. Okay 81.1 84.0 85.5
Austin, U.S.A. Okay 60.0 60.2 60.5
Amsterdam3, Netherlands Okay 89.4 100.1 108.9
London, United Kingdom Okay 86.3 86.8 87.3
Stockholm, Sweden Okay 106.2 109.6 112.7
Madrid, Spain Okay 111.3 111.7 112.1
Sydney, Australia Okay 219.8 220.2 221.2
Amsterdam, Netherlands Okay 93.4 96.7 97.7
Cologne, Germany Okay 101.1 101.5 101.8
Munchen, Germany Okay 101.1 101.5 101.8
Kraków, Poland Okay 125.2 125.6 125.8
Lille, France Okay 90.1 90.6 91.6
Cagliari, Italy Okay 128.0 128.3 128.6
Copenhagen, Denmark Okay 101.0 104.5 107.6
Hong Kong, China Okay 230.7 244.9 259.2
Melbourne, Australia Okay 246.8 247.4 248.5
Singapore, Singapore Okay 261.5 261.7 261.9
Amsterdam2, Netherlands Okay 89.6 99.8 109.2
Porto Alegre, Brazil Okay 153.2 159.0 161.9
Paris, France Okay 107.8 112.2 117.6
Shanghai, China Packets lost (10%) 299.7 300.6 303.4
Vancouver, Canada Packets lost (70%) 65.1 65.5 65.7
San Francisco, U.S.A. Packets lost (40%) 42.6 42.8 43.0
Florida, U.S.A. Packets lost (80%) 26.0 26.1 26.2
New York, U.S.A. Packets lost (70%) 55.4 55.5 55.5
Austin2, U.S.A. Packets lost (60%) 9.6 9.7 9.8
Austin, U.S.A. Packets lost (30%) 9.6 9.7 9.8
Santa Clara, U.S.A. Packets lost (50%) 50.0 82.0 209.1
Amsterdam3, Netherlands Packets lost (40%) 129.2 129.3 129.4
Sydney, Australia Packets lost (90%) 191.9 191.9 191.9
Amsterdam2, Netherlands Packets lost (70%) 129.5 129.6 129.6
Amsterdam, Netherlands Packets lost (80%) 125.8 127.8 129.7
Madrid, Spain Packets lost (90%) 149.6 149.6 149.6
Lille, France Packets lost (30%) 137.0 138.9 142.7
Munchen, Germany Packets lost (60%) 132.0 132.1 132.3
Copenhagen, Denmark Packets lost (50%) 141.8 141.9 142.1
Hong Kong, China Packets lost (70%) 238.9 251.1 257.6
Cagliari, Italy Packets lost (40%) 179.1 186.1 205.5
Paris, France Packets lost (30%) 136.8 139.4 140.6
Singapore, Singapore Packets lost (60%) 232.3 235.3 237.1
Shanghai, China Packets lost (60%) 273.3 273.6 274.0
London, United Kingdom Packets lost (30%) 106.4 106.8 107.1
Porto Alegre, Brazil Packets lost (20%) 165.8 171.5 176.5
Stockholm, Sweden Packets lost (100%)
Cologne, Germany Packets lost (100%)
Kraków, Poland Packets lost (90%) 165.9 165.9 165.9
Melbourne, Australia Packets lost (90%) 220.3 220.3 220.3