Use modem to access the Internet in redhat9

Article Title: use modem to access the Internet in redhat9. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source.
Nowadays, Linux is becoming more and more powerful, and Linux is becoming more and more convenient to use. More and more modem families are joining the ranks of Linux users. However, many users are still using script dial-up to access the Internet; in fact, there are also very convenient graphical interface access tools under Linux, but many people do not know how to use it.
　　
Since ppp, TCP/IP, and other kernel settings are already preset by RedHat, the people who use RedHat do not need to compile the core work if they need to dial the Internet, you only need to set the dialing ISP parameter. Here I will mainly describe the PAP connection method. If you do not provide an ISP or phone number for the PAP connection, you can use the software to dial the phone number. However, do not enable the PAP option, in addition, you must take a careful look at the setting of "sending CT" <--> "send.
　　
1. Set modem
　　
No matter which method the user uses to dial up the Internet, some modem and network settings must be done first. The first is to set the serial port of the modem, you can run "modemtool" in a window under X as root, or run "modemtool" in control-panel of RedHat ":
　　
Select the location of your modem connection and then press "OK ". Run "netcfg". You can also run it in the control-panel of RedHat:
　　
In this screen, enter the IP address of your DNS server (nameserver). However, the IP address to enter depends on the ISP that provides the messenger for dial-up Internet access, after filling out the archive, do not forget to press "save. The above screen contains the IP addresses of the two DNS servers. when surfing the Internet, the program will first query the name of the host to be connected on the DNS server with the first IP address, if the server cannot be found (this DNS server may be on the machine), the server with the second IP address will be checked again. Generally, it is enough to fill in one DNS server.
　　
2. Set netcfg connection
Select "PPP" and press "OK". Then, a window will pop up asking you to enter the PPP setting value. after entering the phone number, account, and password to be played, click "Use PAP authentication. You can "Customize" to set your modem parameters and network parameters. It is particularly worth mentioning that the "Allow any user to (de) activate interface" option, if this option is selected, any user can start this PPP connection, not necessarily using the root identity to dial the Internet. In addition, the user who does not need PAP should also adjust it here:
　　
Enter the IP address of your DNS server (nameserver) Here, But the IP address to enter depends on the ISP that provides the user to dial the Internet.
　　
3. dial-up Internet access
　　
Press "Activate" to start the PPP connection you just joined. After dialing, the connection is completed. Next, you can open a window to check whether ppp0 is up with/sbin/ifconfig, to end the connection, click "Deactivate" to make ppp0 inactive. However, sometimes pressing "Deactivate" does not work, but you must manually kill pppd. You can use the root identity to open a window and execute "ps ax | grep pppd" to find the pppd pid, then kill-9 to kill pppd, as shown in the following example:
　　
# Ps ax | grep pppd
　　
7467 p1 S/usr/sbin/pppd-detach lock modem crtscts defaultroute name
　　
7502 p1 S grep pppd
　　
# Kill-9 7467
　　
# Ps ax | grep pppd 7507 p1 S 0: 00 grep pppd
　　
#
　　
It is very easy to start PPP connections with netcfg, but only root has the permission to start netcfg. How do users start PPP? Rest assured that RedHat has already planned the dial-up Internet access method for general users for us. As long as you have installed the rpm suite usernet and select "Allow any user to (de) when setting the PPP connection) activate interface "option. Generally, users can execute" usernet "under X to dial the internet." usernet "lists the network interfaces that users can control, such:
　　
Red indicates that the device is not started. You only need to click the desired Network Interface (ppp0 is the only one here), and the system will dial the Internet and wait until it turns green, it indicates that the connection is successful. It is simple enough!