在现代网络管理中，Telnet服务器扮演着重要的角色，它允许远程用户通过TCP/IP协议连接到系统，进行命令行操作和管理，对于使用Ubuntu系统的用户来说，安装和配置Telnet服务器是一个相对简单的过程，本文将详细介绍如何在Ubuntu上安装和配置Telnet服务器，确保你能够顺利运行和管理你的网络环境。

准备工作

在开始之前，请确保你已经安装了Ubuntu操作系统，并且系统是最新的，还需要确保系统中已经安装了必要的软件包，可以使用以下命令来检查和安装这些软件包：

sudo apt update
sudo apt upgrade
sudo apt install net-tools

apt update命令用于更新软件包列表，apt upgrade用于升级系统中已有的软件包到最新版本，apt install net-tools用于安装Net-Tools工具集，其中包含了Telnet服务器所需的软件包。

安装Telnet服务器

我们将通过添加一个Telnet服务器到系统中来启动Telnet服务，首先需要编辑/etc/apt/sources.list文件，添加Telnet服务器的官方仓库地址：

sudo nano /etc/apt/sources.list

在文件末尾添加以下内容：

deb http://archive.ubuntu.com/ubuntu/ focal main multiverse

保存并退出编辑器后，再次运行apt update和apt upgrade命令来更新软件包列表并安装Telnet服务器软件包：

sudo apt update
sudo apt upgrade -y telnet

重启网络服务以应用更改：

sudo systemctl restart network

配置文件设置

为了安全起见，建议为Telnet服务创建一个专用的用户账户，并限制其权限，可以通过编辑/etc/security/limits.conf文件来实现这一点：

sudo nano /etc/security/limits.conf

在文件末尾添加以下行：

soft nofile 65536
hard nofile 131072
telnet_user ttyS0 999999999 999999999 65536:65536 7448:7448 * timers /proc /sys /bin/sh * syslogd /usr/bin/syslogd * kbd /usr/bin/kbd * wall /usr/bin/wall * mail /usr/bin/mail * remote-fs /usr/bin/remote-fs * CLOCK_TAILCALL for /dev/ clock /usr/bin/CLOCK_TAILCALL for /dev/clock * ftp-data /usr/libexec/ftp-data * gssproxy /usr/libexec/gssproxy * GSSAPI-credspec /usr/libexec/GSSAPI-credspec * GSSAPI-creddef /usr.libexec/GSSAPI-creddef * GSSAPI-creddef-in /usr.libexec/GSSAPI-creddef-in * GSSAPI-mech /usr.libexec/GSSAPI-mech * GSSAPI-krb5 /usr.libexec/GSSAPI-krb5 * Kerberos5-preconfig /usr.libexec/Kerberos5-preconfig * local-fs /usr/bin/local-fs * remote-fs /usr/bin/remote-fs * remote-shell /usr/bin/remote-shell * remote-login /usr/bin/remote-login * remote-host any,any ::1,::1 ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h ::1 %h * login delay none * remote-pipelining any * remote-pipelining yes * remote-pipelining any * remote-pipelining yes * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * local-root any * locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +locks max +localport tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tcp -maxconn tephenhancer offEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO_NEWLINEEND NO