One of the advantages of using Google App Engine is that your applications can run in various data centers around the world (i.e. the cloud). So if your users are far away (like I was in South Africa last week) they can use servers that are closer. Google can fake IP addresses, routers, etc.
SO as an experiment, while I was in South Africa I did a trace route to my appspot application and then did the same trace route from a server in Michigan. The results are not very conclusive – but I put them here so I can come back and check again later.
I do get a quite different IP address from South Africa compared with Michigan – but the traceroute in either case seems to lead to southern California. These were done at pretty much the same time – I was logged into my Michigan server using SSH.
---- From South Africa ----- traceroute wiscrowd.appspot.com traceroute to appspot.l.google.com (209.85.129.141), 64 hops max, 40 byte packets 1 172.16.64.1 (172.16.64.1) 64.578 ms 1.804 ms 3.092 ms 2 uwcfw-int.uwc.ac.za (192.102.9.1) 1.174 ms 1.951 ms 4.738 ms 3 uwc-uninet-router.uwc.ac.za (196.11.235.3) 37.678 ms 176.863 ms 142.694 ms 4 unknown.uni.net.za (155.232.144.173) 88.820 ms 7.056 ms 579.962 ms 5 v2750-tiger-brie.uni.net.za (155.232.145.226) 303.990 ms 13.773 ms 11.636 ms 6 unknown.uni.net.za (196.32.209.25) 552.896 ms 597.400 ms 613.206 ms 7 74.125.50.133 (74.125.50.133) 613.780 ms 532.660 ms 305.131 ms 8 209.85.252.76 (209.85.252.76) 320.321 ms 209.85.255.175 (209.85.255.175) 603.594 ms 610.238 ms 9 72.14.233.63 (72.14.233.63) 610.531 ms 209.85.248.80 (209.85.248.80) 317.499 ms 611.633 ms 10 72.14.232.209 (72.14.232.209) 303.452 ms 209.85.248.183 (209.85.248.183) 288.133 ms 72.14.232.209 (72.14.232.209) 302.015 ms 11 72.14.232.203 (72.14.232.203) 626.897 ms 610.341 ms 388.027 ms 12 72.14.233.210 (72.14.233.210) 534.247 ms 72.14.239.170 (72.14.239.170) 536.955 ms 72.14.233.210 (72.14.233.210) 610.059 ms 13 209.85.129.141 (209.85.129.141) 614.124 ms 609.336 ms 607.647 ms --- From Michigan --- zaxxon% /usr/sbin/traceroute wiscrowd.appspot.com traceroute to appspot.l.google.com (74.125.19.141), 30 hops max, 40 byte packets 1 v-umce-login.r-aldca.umnet.umich.edu (141.211.2.130) 0.251 ms 0.210 ms 0.192 ms 2 198-108-11-160.umnet.umich.edu (198.108.11.160) 0.591 ms 0.431 ms 0.394 ms 3 l3-arbl-fxb.r-arbl.umnet.umich.edu (141.211.0.137) 0.541 ms 0.532 ms 0.493 ms 4 l3-barb-rarb.r-bin-arbl.umnet.umich.edu (192.12.80.129) 0.441 ms 0.430 ms 0.392 ms 5 v-bin-arbl-inet-aa.merit-wsu5.merit.edu (192.12.80.69) 1.890 ms 1.880 ms 1.890 ms 6 xe-0-1-0x76.eq-chi2.mich.net (198.108.23.12) 7.781 ms 7.721 ms 7.731 ms 7 198.110.131.78 (198.110.131.78) 8.130 ms 7.969 ms 7.981 ms 8 216.239.48.154 (216.239.48.154) 8.079 ms 8.121 ms 209.85.250.237 (209.85.250.237) 8.132 ms 9 209.85.249.19 (209.85.249.19) 30.485 ms 30.383 ms 30.295 ms 10 209.85.242.211 (209.85.242.211) 56.051 ms 56.143 ms 55.801 ms 11 209.85.243.122 (209.85.243.122) 55.950 ms 56.291 ms 56.152 ms 12 209.85.251.94 (209.85.251.94) 56.103 ms 64.126 ms 56.202 ms 13 cf-in-f141.google.com (74.125.19.141) 56.199 ms 56.288 ms 56.352 ms