安装 localtunnel 时出现此错误：
sudo gem install localtunnel
[sudo] password for anr:
ERROR: Could not find a valid gem 'localtunnel' (>= 0) in any repository
ERROR: Possible alternatives: localone, rack-tunnel
这就是我得到的traceroute rubygems.org：
traceroute rubygems.org
traceroute to rubygems.org (54.245.255.174), 30 hops max, 60 byte packets
1 192.168.100.1 (192.168.100.1) 2.882 ms 2.868 ms 3.900 ms
2 dsl-ap-static-001.92.144.59.airtelbroadband.in (59.144.92.1) 22.183 ms 27.974 ms 27.970 ms
3 ABTS-AP-Static-250.240.169.122.airtelbroadband.in (122.169.240.250) 23.142 ms 27.824 ms 31.209 ms
4 125.16.7.125 (125.16.7.125) 31.243 ms 33.142 ms 37.945 ms
5 182.79.255.33 (182.79.255.33) 334.176 ms 341.682 ms 347.246 ms
6 nyiix-peering.amazon.com (198.32.160.64) 349.918 ms 293.726 ms 293.576 ms
7 178.236.3.179 (178.236.3.179) 293.436 ms 299.831 ms 298.774 ms
8 178.236.3.189 (178.236.3.189) 323.077 ms 319.980 ms 178.236.3.187 (178.236.3.187) 341.363 ms
9 72.21.222.246 (72.21.222.246) 340.243 ms 72.21.222.232 (72.21.222.232) 342.429 ms 344.028 ms
10 205.251.232.103 (205.251.232.103) 326.301 ms 334.583 ms 205.251.232.105 (205.251.232.105) 354.295 ms
11 205.251.232.207 (205.251.232.207) 340.857 ms 205.251.232.213 (205.251.232.213) 349.718 ms 205.251.232.207 (205.251.232.207) 340.789 ms
12 205.251.230.127 (205.251.230.127) 342.020 ms 323.848 ms 321.291 ms
13 ec2-50-112-0-141.us-west-2.compute.amazonaws.com (50.112.0.141) 334.590 ms ec2-50-112-0-207.us-west-2.compute.amazonaws.com (50.112.0.207) 326.941 ms 324.361 ms
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我还尝试按照 askubuntu 的建议安装一些代理。