Domain-Name-System
無法從 Mac OSX Lion 訪問站點，但可以從網路上的其他電腦訪問？
解決了：
問題出在 hamachi 客戶端，hamachi 正在劫持所有 5.0.0.0/8 地址塊
- http://en.wikipedia.org/wiki/Hamachi_(software)#Criticism
- http://b.logme.in/2012/11/07/changes-to-hamachi-on-november-19th/
Mac 上的修復
- LogMeIn Hamachi > 首選項 > 設置 > 高級 > 對等連接 > IP 協議模式 > 僅 IPv6（預設為兩者）
如果您只能通過 IPv4 連接到您的某些網路，則此“修復”對您不起作用
—–
幾週前，我開始使用一項服務 - https://semaphoreapp.com 我認為他們在一周前進行了 DNS 更改，因為我無法從我的 Mac OSX Lion (10.7.4) 機器（我的主要開發機器）訪問該站點)
但我可以從我網路上的其他機器訪問該站點
- 平板電腦
- 窗戶機
- 麥迷你 (10.6.8)
經過一些Google搜尋後，我嘗試了這兩個
- dscacheutil -flushcache
- sudo killall -HUP mDNSResponder
但是不行，我也聯繫了 semaphoreapp，但到目前為止還沒有聯繫 - 同樣有趣的是，我的一位同事也遇到了完全相同的問題，無法通過 Mac OSX Lion 訪問，但可以通過 Windows 機器訪問，我們遠端工作並且不在同一個 ISP
一些附加資訊
Lion (10.7.4) 無法訪問網站
host semaphoreapp.com semaphoreapp.com has address 5.9.53.16 ping semaphoreapp.com PING semaphoreapp.com (5.9.53.16): 56 data bytes Request timeout for icmp_seq 0 Request timeout for icmp_seq 1 Request timeout for icmp_seq 2 Request timeout for icmp_seq 3 ping: sendto: No route to host Request timeout for icmp_seq 4 ping: sendto: Host is down Request timeout for icmp_seq 5 ping: sendto: Host is down Request timeout for icmp_seq 6 ping: sendto: Host is down Request timeout for icmp_seq 7 .... traceroute semaphoreapp.com traceroute to semaphoreapp.com (5.9.53.16), 64 hops max, 52 byte packets 1 * * * 2 * * * traceroute: sendto: No route to host 3 traceroute: wrote semaphoreapp.com 52 chars, ret=-1 *traceroute: sendto: Host is down traceroute: wrote semaphoreapp.com 52 chars, ret=-1 ....MacMini (10.6.8) 可以訪問它
host semaphoreapp.com semaphoreapp.com has address 5.9.53.16 ping semaphoreapp.com PING semaphoreapp.com (5.9.53.16): 56 data bytes 64 bytes from 5.9.53.16: icmp_seq=0 ttl=44 time=191.458 ms 64 bytes from 5.9.53.16: icmp_seq=1 ttl=44 time=202.923 ms 64 bytes from 5.9.53.16: icmp_seq=2 ttl=44 time=180.746 ms 64 bytes from 5.9.53.16: icmp_seq=3 ttl=44 time=200.616 ms 64 bytes from 5.9.53.16: icmp_seq=4 ttl=44 time=178.818 ms .... traceroute semaphoreapp.com traceroute to semaphoreapp.com (5.9.53.16), 64 hops max, 52 byte packets 1 192.168.0.1 (192.168.0.1) 1.677 ms 1.446 ms 1.445 ms 2 * LOCAL ISP 11.957 ms * 3 etc... 10.704 ms 14.183 ms 9.341 ms 4 etc... 32.641 ms 12.147 ms 10.850 ms 5 etc.... 44.205 ms 54.563 ms 36.243 ms 6 vlan139.car1.seattle1.level3.net (4.53.145.165) 50.136 ms 45.873 ms 30.396 ms 7 ae-32-52.ebr2.seattle1.level3.net (4.69.147.182) 31.926 ms 40.507 ms 49.993 ms 8 ae-2-2.ebr2.denver1.level3.net (4.69.132.54) 78.129 ms 59.674 ms 49.905 ms 9 ae-3-3.ebr1.chicago2.level3.net (4.69.132.62) 99.019 ms 82.008 ms 76.074 ms 10 ae-1-100.ebr2.chicago2.level3.net (4.69.132.114) 96.185 ms 75.658 ms 75.662 ms 11 ae-6-6.ebr2.washington12.level3.net (4.69.148.145) 104.322 ms 105.563 ms 118.480 ms 12 ae-5-5.ebr2.washington1.level3.net (4.69.143.221) 93.646 ms 99.423 ms 96.067 ms 13 ae-41-41.ebr2.paris1.level3.net (4.69.137.49) 177.744 ms ae-44-44.ebr2.paris1.level3.net (4.69.137.61) 199.363 ms 198.405 ms 14 ae-47-47.ebr1.frankfurt1.level3.net (4.69.143.141) 176.876 ms ae-45-45.ebr1.frankfurt1.level3.net (4.69.143.133) 170.994 ms ae-46-46.ebr1.frankfurt1.level3.net (4.69.143.137) 177.308 ms 15 ae-61-61.csw1.frankfurt1.level3.net (4.69.140.2) 176.769 ms ae-91-91.csw4.frankfurt1.level3.net (4.69.140.14) 178.676 ms 173.644 ms 16 ae-2-70.edge7.frankfurt1.level3.net (4.69.154.75) 180.407 ms ae-3-80.edge7.frankfurt1.level3.net (4.69.154.139) 174.861 ms 176.578 ms 17 as33891-net.edge7.frankfurt1.level3.net (195.16.162.94) 175.448 ms 185.658 ms 177.081 ms 18 hos-bb1.juniper4.rz16.hetzner.de (213.239.240.202) 188.700 ms 190.332 ms 188.196 ms 19 hos-tr4.ex3k14.rz16.hetzner.de (213.239.233.98) 199.632 ms hos-tr3.ex3k14.rz16.hetzner.de (213.239.233.66) 185.938 ms hos-tr2.ex3k14.rz16.hetzner.de (213.239.230.34) 182.378 ms 20 * * * 21 * * * 22 * * *有任何想法嗎？
**編輯：**添加 tcpdump
MacMini（可以連接）在執行時 -
ping semaphoreapp.comsudo tcpdump -v -i en0 dst semaphoreapp.com Password: tcpdump: listening on en0, link-type EN10MB (Ethernet), capture size 65535 bytes 17:33:03.337165 IP (tos 0x0, ttl 64, id 20153, offset 0, flags [none], proto ICMP (1), length 84, bad cksum 0 (->3129)!) 192.168.0.6 > static.16.53.9.5.clients.your-server.de: ICMP echo request, id 61918, seq 0, length 64 17:33:04.337279 IP (tos 0x0, ttl 64, id 26049, offset 0, flags [none], proto ICMP (1), length 84, bad cksum 0 (->1a21)!) 192.168.0.6 > static.16.53.9.5.clients.your-server.de: ICMP echo request, id 61918, seq 1, length 64 17:33:05.337425 IP (tos 0x0, ttl 64, id 47854, offset 0, flags [none], proto ICMP (1), length 84, bad cksum 0 (->c4f3)!) 192.168.0.6 > static.16.53.9.5.clients.your-server.de: ICMP echo request, id 61918, seq 2, length 64 17:33:06.337548 IP (tos 0x0, ttl 64, id 24772, offset 0, flags [none], proto ICMP (1), length 84, bad cksum 0 (->1f1e)!) 192.168.0.6 > static.16.53.9.5.clients.your-server.de: ICMP echo request, id 61918, seq 3, length 64 17:33:07.337670 IP (tos 0x0, ttl 64, id 8171, offset 0, flags [none], proto ICMP (1), length 84, bad cksum 0 (->5ff7)!) 192.168.0.6 > static.16.53.9.5.clients.your-server.de: ICMP echo request, id 61918, seq 4, length 64 17:33:08.337816 IP (tos 0x0, ttl 64, id 35810, offset 0, flags [none], proto ICMP (1), length 84, bad cksum 0 (->f3ff)!) 192.168.0.6 > static.16.53.9.5.clients.your-server.de: ICMP echo request, id 61918, seq 5, length 64 17:33:09.337948 IP (tos 0x0, ttl 64, id 31120, offset 0, flags [none], proto ICMP (1), length 84, bad cksum 0 (->652)!) 192.168.0.6 > static.16.53.9.5.clients.your-server.de: ICMP echo request, id 61918, seq 6, length 64 ^C 7 packets captured 1047 packets received by filter 0 packets dropped by kernel執行時 OSX Lion（無法連接）-
ping semaphoreapp.com# wireless ~ $ sudo tcpdump -v -i en1 dst semaphoreapp.com Password: tcpdump: listening on en1, link-type EN10MB (Ethernet), capture size 65535 bytes ^C 0 packets captured 262 packets received by filter 0 packets dropped by kernel和
# wired ~ $ sudo tcpdump -v -i en0 dst semaphoreapp.com tcpdump: listening on en0, link-type EN10MB (Ethernet), capture size 65535 bytes ^C 0 packets captured 219 packets received by filter 0 packets dropped by kernel
Request timeout for icmp_seqping 25 或 30 次後以上輸出。我對 tcpdump 了解不多，但對我來說，ping 請求似乎沒有離開我的機器？
您是否在無法連接到 semaphoreapp.com 的機器上執行 Hamachi？
如果是，我可以建議您禁用 Hamachi 並重試連接嗎？您可以在以下位置找到有關 Hamachi 街區的更多資訊：
DNS 解析看起來不錯，因為您可以將名稱解析為正確的 IP 地址。我可以訪問 Lion 和 Mountain Lion 中的站點。
您可以嘗試重新啟動網路介面。
sudo ifconfig en0 down sudo ifconfig en0 up將 en0 替換為正在使用的網路介面。使用不帶參數的 ifconfig 來找出正確的介面。
如果您使用兩個網路介面——例如無線和有線——這可能會導致問題。
如果您使用的 VPN 可能會導致問題。基本上尋找您的 Lion 盒子上的網路配置可能與您的其他主機上不同的任何方式。
而且，儘管它可能很蹩腳，如果您還沒有嘗試過，可能需要重新啟動:)