请教一个奇怪的网络连通性问题

[qingmuhy0]

root@wiki-4837-pre:~# curl -I http://www.gstatic.com/generate_204
curl: (28) Failed to connect to www.gstatic.com port 80 after 3067 ms: Couldn't connect to server
root@wiki-4837-pre:~# curl -I http://www.gstatic.com/generate_204 -vv
* Host www.gstatic.com:80 was resolved.
* IPv6: 2607:f8b0:4007:810::2003
* IPv4: 142.250.189.3
*   Trying 142.250.189.3:80...
*   Trying [2607:f8b0:4007:810::2003]:80...
* Immediate connect fail for 2607:f8b0:4007:810::2003: Network is unreachable
* connect to 142.250.189.3 port 80 from 172.247.*.* port 53350 failed: Connection timed out
* Failed to connect to www.gstatic.com port 80 after 3100 ms: Couldn't connect to server
* Closing connection
curl: (28) Failed to connect to www.gstatic.com port 80 after 3100 ms: Couldn't connect to server
root@wiki-4837-pre:~# nexttrace 142.250.189.3
NextTrace v1.3.4 2024-09-10T13:25:26Z 6a3ea6a
2024/10/15 11:46:23 IP connection has been timeout, please check your network
[NextTrace API] preferred API IP -  - ms - Get "https://45.88.195.154:443/v3/challenge/request_challenge": dial tcp 45.88.195.154:443: connect: connection timed out
RetToken failed 3 times, please try again after a while, exit
root@wiki-4837-pre:~# 

一个上游是 cera 的 4837 优化线路，我连接服务器和 ping 服务器都正常，ssh 连接也正常。

但是从 vps 访问其他网站就时不时啥也连不上，这到底是啥问题啊，有点摸不着头脑。

[qingmuhy0]

```shell
root@wiki-4837-pre:~# ping 142.250.68.99
PING 142.250.68.99 (142.250.68.99) 56(84) bytes of data.
64 bytes from 142.250.68.99: icmp_seq=1 ttl=57 time=0.340 ms
64 bytes from 142.250.68.99: icmp_seq=2 ttl=57 time=0.306 ms
64 bytes from 142.250.68.99: icmp_seq=3 ttl=57 time=0.330 ms
```
ping 那个 IP 的话，也是能通的。

[qingmuhy0]

这个问题，是时不时出现的，一会通，一会不通，这是机房的问题嘛。
重装系统都试过了，还是一样的。

[basncy]

#1 这结果, 细思极恐. 检查一下什么 app 干的.

[qingmuhy0]

感觉就是机房问题，icmp 正常，tcp 时不时不通，玄学问题。

[lcy630409]

关 ipv6 保平安