YoLinux Tutorial - Configuring Linux PPP Dial-in
Configuration of Linux system to provide PPP for dial-in services.
It would be wise to have a dedicated phone line as the modem will be
configured to answer all calls.
Piece in work - Still trying to figure it all out - don't believe a word I say on this page!!!
Point to Point Protocol, or ppp, is used to create your connection over
one's analog telephone modem.
Your computer will use communication ports,
known as "COM" ports to access your modem.
Linux will refer to these hardware COM ports as Unix devices as follows:
-
| Linux Device | DOS com port number | I/O Address | IRQ | Major Device # | Minor Device # |
|---|
| /dev/ttyS0 | COM1 (Incomming) | 3F8 | 4 | 4 | 64 |
| /dev/cua0 | COM1 (Outgoing) | 3F8 | 4 | 5 | 64 |
| /dev/ttyS1 | COM2 (Incomming)
(Typically used for external modems) | 2F8 | 3 | 4 | 65 |
| /dev/cua1 | COM2 (Outgoing) | 2F8 | 3 | 5 | 65 |
| /dev/ttyS2 | COM3 (Incomming) | 3E8 | 4 | 4 | 66 |
| /dev/cua2 | COM3 (Outgoing) | 3E8 | 4 | 5 | 66 |
| /dev/ttyS3 | COM4 (Incomming) | 2E8 | 3 | 4 | 67 |
| /dev/cua3 | COM4 (Outgoing) | 2E8 | 3 | 5 | 67 |
This example is the manual configuration specific to Red Hat 5.2 /6.0/6.1/6.2
and a US Robotics 56k modem.
Perform the following configuration as user root.
Configure modem and serial line:
Edit the following files:
- Edit file: /etc/inittab (add to end of file)
S1:2345:respawn:/sbin/uugetty ttyS1 115200 vt100
Re-read inittab file. Issue command telinit q (or re-boot)
Found this in a news group:
#Then we check your current modem setup:
AT&V
#What you don't want to see is S0=1. We want to return your modem back to #it's factory default settings so:
AT&F
#Next we save the configuration:
AT&W
#edit /etc/inittab. Look for the line that looks like:
2:123:respawn:/sbin/mingetty tty2
#and change it to:
2:123:respawn:/sbin/agetty -w -I 'ATE0Q1&D2&C1S0=\015' 115200 ttyS1 vt100 #save the file. (or mgetty??)
In "Peter H." writes:
]#The problem here is you need agetty, not mgetty. Here we go:
]#su to root and run minicom
No. agetty is NOT appropriate. mgetty is the getty of choice for any serial port service and especially for a modem.
]#Then we check your current modem setup:
]AT&V
]#What you don't want to see is S0=1. We want to return your modem back to
Agreed. The modem MUST not answer the phone for mgetty to work.
]#it's factory default settings so:
]AT&F
]#Next we save the configuration:
]AT&W
]#edit /etc/inittab. Look for the line that looks like:
]2:123:respawn:/sbin/mingetty tty2
]#and change it to:
]2:123:respawn:/sbin/agetty -w -I 'ATE0Q1&D2&C1S0=\015' 115200 ttyS1 vt100
No. Do NOT use agetty.
]#save the file.Then:
]shutdown -r now
]#the system reboots and you're taking incoming requests...
]#Peter
]In article , "Maximus"
] looked down upon the people and proclaimed:
]> If you are experienced with Linux, specifically mgetty + pppd I need ]> your help. I need to get a dial-in server working. I
can use minicom ]> to dial out, and manually connect a received call. However, no matter ]> what I do mgetty always causes an
"respawning too fast" error.
This means that there is some configuration error so that mgetty stops when it tries to come up.
Add
-x 8
to the mgetty line in inittab. also put
debug 8
into /etc/mgetty*/mgetty.config
so you see exactly what is going on . Then look in /var/log/mgetty* for the messages, and see what the problem is.
Valid baud rates: 300, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200, 230400, 460800
uugetty man page
inittab man page
- Copy the file /usr/doc/getty_ps-2.0.7j/Examples/default/uugetty.autoanswer
to
/etc/default/uugetty.ttyS1
Edit file: /etc/default/uugetty.autoanswer - Change:
ALTLOCK=cua2
to:
ALTLOCK=ttyS1
- Edit file: /etc/mgetty+sendfax/mgetty.config:
/AutoPPP/ - - /usr/sbin/pppd
OR:
/AutoPPP/ - - /usr/sbin/pppd /etc/ppp/options.server
Where /etc/ppp/options.server holds specific pppd options for dial-up to this server.
PPP configuration:
/etc/ppp/options - File should look like this:
debug - log transactions to /var/log/messages
auth -chap +pap login
modem - Serial link is connected to a modem
crtscts - Use hardware flow control
asyncmap 0 - Choice of mapping of control characters
netmask 255.255.255.0
proxyarp - Answer arp requests
ms-dns XXX.XXX.XXX.XXX - DNS name server
lock - Don't let other processes besides PPP use the device
Other options to look at: ms-wins, login, mtu, mru, deflate ...
/etc/ppp/options.ttyS1 - Assign an IP address to dial in client.
XXX.XXX.XXX.XX1:XXX.XXX.XXX.XX2
Where the first IP address is the address of the server and the second is the
IP address assigned to the dial in user.
See file /var/log/messages for diagnostic messages. Requires "debug"
option in /etc/ppp/options file.
Configuration Done!
| Alternate login configuration (Previous method is better): |
Alternately one can give the mode the command: ATE1Q0V1&C1&S0S0=1&W
It is stored it with the modem comand AT&W
Configure user account for auto ppp:
user1:x:901:901::/home/user1:/opt/bin/run-dial-in-ppp
/opt/bin/run-dialin-ppp - File should look like this:
exec /usr/sbin/pppd -detach
-
| Standard Name | Bits Per Second (BPS) |
|---|
| V.90 (V.PCM) | 56,600 |
| V.34 (V.PCM) | 28,800 |
| V.32 (turbo) | 19,200 |
| V.32 (bis) | 14,400 |
| V.32 | 9,600 |
| V.22 (bis) | 2,400 |
| V.22 | 1,200 |
| V.21 | 300 |
| V.29 (Group III FAX) | 9,600 |
| V.27ter (Group III FAX) | 4,800 |
| V.17ter (Group III FAX) | 14,400 |
mgetty Links:
Copyright © 2001 by Greg Ippolito