mosh安装学习——一个基于UDP的ssh服务

mosh是一个远程终端应用，它采用udp的通信方式进行ssh连接。它的作用包括支持不稳定的连接，恢复会话时仍能保持连接。

它适用于网络不稳定的环境中，能将SSH连接的响应时间降到最低。

安装

Debian、Ubuntu：

apt-get update
apt-get install mosh

RHEL/CentOS/Fedora:

yum update
yum install mosh

使用

当我们通过包管理工具安装好mosh后，它已经默认启动了服务程序。例如

mosh-server new -c 8 -s -l LANG=zh_CN.UTF-8 -l LANGUAGE=zh_CN:en_US:en -l LC_NUMERIC=zh_CN.UTF-8 -l LC_TIME=zh_CN.UTF-8 -l LC_MONETARY=zh_CN.UTF-8 -l LC_PAPER=zh_CN.UTF-8 -l LC_NAME=zh_CN.UTF-8 -l LC_ADDRESS=zh_CN.UTF-8 -l LC_TELEPHONE=zh_CN.UTF-8 -l LC_MEASUREMENT=zh_CN.UTF-8 -l LC_IDENTIFICATION=zh_CN.UTF-8

端口问题

它默认采用udp的60001端口，在这种情况下需要我们关闭防火墙或者打开指定端口

iptables -I INPUT -p udp --dport 60001 -j ACCEPT

字符集设置问题

在正式连接之前，我们需要设置需要登录用户的字符集，如果不设置，就会报以下错误：

The locale requested by LANG=en_US.UTF-8 isn't available here.
Running `locale-gen en_US.UTF-8' may be necessary.

The locale requested by LANG=zh_CN.UTF-8 isn't available here.
Running `locale-gen zh_CN.UTF-8' may be necessary.

mosh-server needs a UTF-8 native locale to run.

Unfortunately, the local environment (LANG=en_US.UTF-8) specifies
the character set "US-ASCII",

The client-supplied environment (LANG=zh_CN.UTF-8) specifies
the character set "US-ASCII".

locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory
LANG=zh_CN.UTF-8
LANGUAGE=zh_CN:en_US:en
LC_CTYPE="zh_CN.UTF-8"
LC_NUMERIC=zh_CN.UTF-8
LC_TIME=zh_CN.UTF-8
LC_COLLATE="zh_CN.UTF-8"
LC_MONETARY=zh_CN.UTF-8
LC_MESSAGES="zh_CN.UTF-8"
LC_PAPER=zh_CN.UTF-8
LC_NAME=zh_CN.UTF-8
LC_ADDRESS=zh_CN.UTF-8
LC_TELEPHONE=zh_CN.UTF-8
LC_MEASUREMENT=zh_CN.UTF-8
LC_IDENTIFICATION=zh_CN.UTF-8
LC_ALL=
Connection to www.conbot.space closed.
/usr/bin/mosh: Did not find mosh server startup message.

为此，我们需要在~/.bashrc中设置：

export LANG=en_US.UTF-8
export LC_ALL=en_US.UTF-8

退出重新登录若出现以下问题:

-bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8): No such file or directory

运行一下命令生成配置文件

localedef -v -c -i en_US -f UTF-8 en_US.UTF-8

登录

接下来，在本地服务器同样安装mosh。

像使用ssh一样使用mosh

mosh test@yourserver.com 

# 指定绑定的udp端口，默认启动时动态端口号从60001到60100
mosh test@yourserver.com -p 60001
mosh test@yourserver.com -p 60002
...
mosh test@yourserver.com -p 60100

# 指定ssh服务的端口号
mosh -ssh="ssh -p 22" test@yourserver.com

更多选项

mosh --help
===================
Usage: /usr/bin/mosh [options] [--] [user@]host [command...]
        --client=PATH        mosh client on local machine
                                (default: "mosh-client")
        --server=COMMAND     mosh server on remote machine
                                (default: "mosh-server")

        --predict=adaptive      local echo for slower links [default]
-a      --predict=always        use local echo even on fast links
-n      --predict=never         never use local echo
        --predict=experimental  aggressively echo even when incorrect

-p PORT[:PORT2]
        --port=PORT[:PORT2]  server-side UDP port or range

        --ssh=COMMAND        ssh command to run when setting up session
                                (example: "ssh -p 2222")
                                (default: "ssh")

        --no-init            do not send terminal initialization string

        --help               this message
        --version            version and copyright information

Please report bugs to mosh-devel@mit.edu.
Mosh home page: http://mosh.mit.edu