一個由於MTU值不合理造成的Frp內網穿透問題的解決

摘要： 個人利用frp在單位的兩個內網穿架設了一個http伺服器, 兩個frp的作業系統均為ubuntu， 配置檔案除埠以外完全正常， 其中一個內網frp穿透完全正常， 而另外一個http和SSH均有問題： frpc檔案如下 [web-bs]typ...

個人利用frp在單位的兩個內網穿架設了一個http伺服器,

兩個frp的作業系統均為ubuntu，

配置檔案除埠以外完全正常，

其中一個內網frp穿透完全正常，

而另外一個http和SSH均有問題：

frpc檔案如下

[web-bs]type = httplocal_ip = 127.0.0.1local_port = 80# use_compression = truecustom_domains = www.mydomain.com
[ssh-bs]type = tcplocal_ip = 127.0.0.1local_port = 22remote_port = 10022 

內網地址http://192.168.1.102/p.php，

外網地址http://www.mydomain.com/p.php

其中一臺出現一個奇怪的故障，內網訪問完全正常；

外網出錯，訪問部分html頁面會出錯（內網完全正常）；

並且內網SSH連線正常，而經過Frp外網穿透的SSH連線斷開，原因不明

檢視frps.log

2018/10/02 10:35:41 [I] [control.go:246] [3e5dcb9dd47ad723] login to server success, get run id [3e5dcb9dd47ad723], server udp port [11111]2018/10/02 10:35:41 [I] [control.go:169] [3e5dcb9dd47ad723] [ssh] start proxy success2018/10/02 10:35:41 [I] [control.go:169] [3e5dcb9dd47ad723] [web] start proxy success2018/10/02 10:40:22 [E] [control.go:152] [3e5dcb9dd47ad723] work connection closed, EOF2018/10/02 10:40:22 [E] [control.go:152] [3e5dcb9dd47ad723] work connection closed, EOF2018/10/02 10:40:22 [I] [control.go:308] [3e5dcb9dd47ad723] control writer is closing2018/10/02 10:40:22 [I] [control.go:407] [3e5dcb9dd47ad723] try to reconnect to server…2018/10/02 10:40:22 [E] [control.go:152] [3e5dcb9dd47ad723] work connection closed, EOF2018/10/02 10:40:22 [E] [control.go:152] [3e5dcb9dd47ad723] work connection closed, EOF2018/10/02 10:40:22 [E] [control.go:152] [3e5dcb9dd47ad723] work connection closed, EOF2018/10/02 10:40:22 [I] [control.go:246] [3e5dcb9dd47ad723] login to server success, get run id [3e5dcb9dd47ad723], server udp port [11111]

檢視frpc.log

2018/10/08 19:08:00 [I] [service.go:319] client login info: ip [222.77.157.34:51590] version [0.21.0] hostname [] os [linux] arch [amd64]2018/10/08 19:08:00 [I] [control.go:196] [c2f2312bf5ab125c] Replaced by client [c2f2312bf5ab125c]2018/10/08 19:08:01 [I] [proxy.go:273] [c2f2312bf5ab125c] [web] http proxy listen for host [bs.fdsyy.net] location []2018/10/08 19:08:01 [I] [control.go:335] [c2f2312bf5ab125c] new proxy [web-bs] success2018/10/08 19:08:18 [I] [proxy.go:87] [c2f2312bf5ab125c] [web] get a new work connection: [222.77.157.34:51590]2018/10/08 19:08:40 [I] [control.go:220] [c2f2312bf5ab125c] control writer is closing2018/10/08 19:08:40 [I] [proxy.go:73] [c2f2312bf5ab125c] [web] proxy closing2018/10/08 19:08:40 [I] [control.go:292] [c2f2312bf5ab125c] client exit success2018/10/08 19:08:40 [W] [newhttp.go:209] http: proxy error: snappy: corrupt input2018/10/08 19:08:41 [I] [service.go:319] client login info: ip [222.77.157.34:51594] version [0.21.0] hostname [] os [linux] arch [amd64]2018/10/08 19:08:41 [I] [control.go:196] [c2f2312bf5ab125c] Replaced by client [c2f2312bf5ab125c]2018/10/08 19:08:41 [I] [proxy.go:273] [c2f2312bf5ab125c] [web] http proxy listen for host [bs.fdsyy.net] location []2018/10/08 19:08:41 [I] [control.go:335] [c2f2312bf5ab125c] new proxy [web-bs] success2018/10/08 19:10:00 [I] [proxy.go:87] [c2f2312bf5ab125c] [web] get a new work connection: [222.77.157.34:51594]2018/10/08 19:10:21 [I] [control.go:220] [c2f2312bf5ab125c] control writer is closing2018/10/08 19:10:21 [I] [proxy.go:73] [c2f2312bf5ab125c] [web] proxy closing2018/10/08 19:10:21 [I] [control.go:292] [c2f2312bf5ab125c] client exit success2018/10/08 19:10:21 [W] [newhttp.go:209] http: proxy error: snappy: corrupt input2018/10/08 19:10:21 [I] [service.go:319] client login info: ip [222.77.157.34:51598] version [0.21.0] hostname [] os [linux] arch [amd64]

SSH登入錯誤提示

[email protected]:/home/frpc# vi2018/10/08 19:20:30 [ERR] yamux: keepalive failed: i/o deadline reached

2018/10/08 19:23:11 [ERR] yamux: keepalive failed: i/o deadline reached

確定frpc.ini和frps.ini配置檔案無誤，內網訪問完全正常；外網出錯；

而同樣的配置，另外一個光貓下的內網穿透正常；

兩個光貓下的網路MTU值不同，一個是1500，一個是1492；而Ubuntu預設的MTU值是1500；考慮可能是MTU設定不合理造成，

《修改MTU值優化網路》請參考：http://www.cainiao.blog/html/20150518185006.html

並確定出合適的MTU值為1492

檢視MTU值

修改本地MTU值

ifconfig eth0 mtu 1492 up

注意此命令重啟後實效，永久修改MTU值參考如下：

Edit the interfaces file to set the mtu when the interface comes up:

$ sudo vi /etc/network/interfaces

Edit the file so it includes the post-up line:

iface eth0 inet dhcp

. . .

post-up /sbin/ifconfig eth0 mtu 1500

至此故障解決