我和我的室友都有单独的路由器，但我们共享同一个 ISP。
为了排除 DNS 问题，我dig smtp-mail.outlook.com连接到个人网络时查找了“smtp-mail.outlook.com”的 IP 地址：
;; QUESTION SECTION:
;smtp-mail.outlook.com. IN A
;; ANSWER SECTION:
smtp-mail.outlook.com. 98 IN CNAME smtp.live.com.
smtp.live.com. 2456 IN CNAME smtp.glbdns2.microsoft.com.
smtp.glbdns2.microsoft.com. 131 IN A 65.55.163.152
然后，在仍然连接到我的个人网络的情况下，我执行了 tcptraceroute：
~ ➜ sudo tcptraceroute 65.55.163.152 587
Selected device en0, address 192.168.1.183, port 51220 for outgoing packets
Tracing the path to 65.55.163.152 on TCP port 587 (submission), 30 hops max
1 192.168.1.1 1.641 ms 0.703 ms 0.657 ms
2 66.158.233.xxx 1.017 ms 1.031 ms 0.909 ms
3 * * *
4 * * *
5 * * *
6 * * *
7 * * *
8 * * *
9 * * *
10 * * *
11 * * *
12 * * *
13 * * *
14 * * *
15 * * *
16 * * *
17 * * *
18 * * *
19 * * *
20 * * *
21 * * *
22 * * *
23 * * *
24 * * *
25 * * *
26 * * *
27 * * *
28 * * *
29 * * *
30 * * *
Destination not reached
随后我连接室友的网络，做了同样的事情。得到了以下回应：
~ ➜ sudo tcptraceroute 65.55.163.152 587
Selected device en0, address 192.168.1.13, port 51161 for outgoing packets
Tracing the path to 65.55.163.152 on TCP port 587 (submission), 30 hops max
1 192.168.1.1 2.245 ms 12.245 ms 1.460 ms
2 66.158.233.xxx 1.861 ms 3.033 ms 1.458 ms
3 237-0-111-208-in-addr-arpa.omnispring.net (208.111.0.237) 4.751 ms 1.842 ms 1.372 ms
4 157-10-111-208-in-addr-arpa.omnispring.net (208.111.10.157) 3.618 ms 6.760 ms 4.132 ms
5 te0-0-1-2.nr11.b006655-1.mco01.atlas.cogentco.com (38.104.89.137) 11.454 ms 5.082 ms 8.654 ms
6 te0-0-1-1.rcr11.mco01.atlas.cogentco.com (154.24.23.201) 5.886 ms 8.745 ms 5.421 ms
7 te0-0-1-0.rcr21.tpa01.atlas.cogentco.com (154.24.44.214) 8.267 ms 7.475 ms 7.079 ms
8 be2745.ccr22.mia01.atlas.cogentco.com (154.54.1.137) 13.722 ms 21.922 ms 14.404 ms
9 be2055.ccr21.mia03.atlas.cogentco.com (154.54.24.234) 14.018 ms 23.091 ms 15.092 ms
10 38.104.94.122 22.733 ms 16.203 ms 11.482 ms
11 ae14-0.mia-96cbe-1b.ntwk.msn.net (198.206.164.165) 13.262 ms 16.312 ms 15.277 ms
12 be-75-0.ibr02.atb.ntwk.msn.net (104.44.224.230) 36.408 ms 35.275 ms 46.426 ms
13 be-3-0.ibr01.bn1.ntwk.msn.net (104.44.4.49) 37.250 ms 546.708 ms 39.023 ms
14 be-1-0.ibr02.bn1.ntwk.msn.net (104.44.4.63) 41.006 ms 38.616 ms 36.900 ms
15 be-3-0.ibr02.was05.ntwk.msn.net (104.44.4.26) 42.879 ms 35.490 ms 43.147 ms
16 ae71-0.bl2-96c-1b.ntwk.msn.net (104.44.8.173) 41.727 ms 35.650 ms 34.375 ms
17 * * *
18 * * *
19 * * *
20 * * *
21 * * *
22 65.55.163.152 [open] 50.886 ms 53.293 ms 48.313 ms
这是什么意思？
编辑
以下是我尝试端口 443 时发生的情况。
sudo tcptraceroute 65.55.163.152 443
Password:
Selected device en0, address 192.168.1.183, port 52721 for outgoing packets
Tracing the path to 65.55.163.152 on TCP port 443 (https), 30 hops max
1 192.168.1.1 5.716 ms 2.333 ms 2.286 ms
2 66.158.233.xxx 5.924 ms 2.056 ms 4.492 ms
3 237-0-111-208-in-addr-arpa.omnispring.net (208.111.0.237) 2.899 ms 4.417 ms 9.569 ms
4 157-10-111-208-in-addr-arpa.omnispring.net (208.111.10.157) 7.469 ms 3.429 ms 3.378 ms
5 te0-0-1-2.nr11.b006655-1.mco01.atlas.cogentco.com (38.104.89.137) 4.240 ms 8.789 ms 5.504 ms
6 te0-0-1-1.rcr11.mco01.atlas.cogentco.com (154.24.23.201) 7.875 ms 8.628 ms 5.733 ms
7 te0-0-1-0.rcr21.tpa01.atlas.cogentco.com (154.24.44.214) 11.645 ms 6.852 ms 6.923 ms
8 be2745.ccr22.mia01.atlas.cogentco.com (154.54.1.137) 18.506 ms 15.501 ms 17.734 ms
9 be2055.ccr21.mia03.atlas.cogentco.com (154.54.24.234) 18.604 ms 14.386 ms 16.901 ms
10 38.104.94.122 12.786 ms 18.877 ms 12.185 ms
11 ae14-0.mia-96cbe-1b.ntwk.msn.net (198.206.164.165) 15.853 ms 17.492 ms 19.043 ms
12 be-75-0.ibr02.atb.ntwk.msn.net (104.44.224.230) 39.239 ms 36.748 ms 43.531 ms
13 be-3-0.ibr01.bn1.ntwk.msn.net (104.44.4.49) 39.055 ms 37.077 ms 38.916 ms
14 be-1-0.ibr02.bn1.ntwk.msn.net (104.44.4.63) 37.130 ms 37.006 ms 36.756 ms
15 be-3-0.ibr02.was05.ntwk.msn.net (104.44.4.26) 36.872 ms 38.863 ms 41.139 ms
16 ae71-0.bl2-96c-1b.ntwk.msn.net (104.44.8.173) 37.641 ms 36.269 ms 34.535 ms
17 * * *
18 * * *
19 * * *
20 * * *
21 * * *
22 * * *
23 * * *
24 * * *
25 * * *
26 * * *
27 * * *
28 * * *
29 * * *
30 * * *
Destination not reached
答案1
根据您更新的信息，我认为您的路由器在端口 80 上运行某种代理，因此数据包的 TTL 永远不会超过 2 并且会超时。通过使用端口 443，您可以避免使用此代理。