Dialing up the Department from a Linux box

These are directions for getting your Linux box to dial up the Mathematics Department and start up a PPP connection using the slirp program. I've only tested it with a couple of versions of RedHat Linux, but it should work with any other distribution too. If you have any problems with it (e.g., if it makes your machine blow up), please have your heirs let me know: psh@math.mit.edu

There are two files that you need to dial up the Department and one more to hang up the connection to the department. There are three numbers you can dial to reach the Department's modems:

1-617-258-7179
1-617-258-8140
1-617-258-6824

Thus, there are a total of seven scripts here: Two for dialing each of the three numbers, plus one to hang up whichever connection you've made. If you're happy dialing the same number every time, then you only need two dialup files and one hangup file.

Apparently, either of the first two phone numbers above (7179 and 8140) is supposed to automatically transfer the incoming call to an unused line, whereas the third number (6824) is just for one particular line. Thus, in theory, either of those first two numbers should be sufficient. Alas, there have been occasional problems with the phone lines leading to the department, and there have been times when neither of the first two numbers would work but the third one would.

To dial 1-617-258-7179 you need mit1-up and chat-mit1.
To dial 1-617-258-8140 you need mit2-up and chat-mit2.
To dial 1-617-258-6824 you need mit3-up and chat-mit3.
To hang up any of those connections, you need mit-down.

Note: Before you can use these scripts, you need to edit the chat scripts to include your MIT username and password. You will also need to change the command prompt if your command prompt doesn't include the tilde "~" character.

Summary of how to get this all working:

Copy the script mit1-up to /usr/local/bin/mit1-up and make sure it's readable and executable by giving the commands (as root)
```
chown root.root /usr/local/bin/mit1-up
chmod 755 /usr/local/bin/mit1-up
```
Copy the chat script chat-mit1 to /etc/ppp/chat-mit1 and make sure it's readable only by root (since it will contain your MIT password) by giving the commands (as root)
```
chown root.root /etc/ppp/chat-mit1
chmod 400 /etc/ppp/chat-mit1
```
Edit the file /etc/ppp/chat-mit1 so that it includes your MIT username and password (just replace USERNAME with your username and PASSWORD with your password). If your command prompt doesn't include the tilde character, then edit the line
```
'~' 'slirp -P'
```
near the bottom of that file to replace that tilde '~' with whatever your command prompt is, e.g., if your command prompt is a percent sign, then you'd want
```
'%' 'slirp -P'
```
or perhaps your prompt requires the line
```
'Command?' 'slirp -P'
```
Copy the script mit-down to /usr/local/bin/mit-down and make sure it's readable and executable by giving the commands (as root)
```
chown root.root /usr/local/bin/mit-down
chmod 755 /usr/local/bin/mit-down
```
Make sure that /dev/modem is a link to the serial port of your modem. If you don't have any file named /dev/modem, but your modem is attached to, e.g., your first serial port, which is ttyS0, then you need to give the command (as root)
```
ln -s /dev/ttyS0 /dev/modem
```
If you don't already have one or more MIT nameservers listed in your /etc/resolv.conf file, add the line
```
nameserver 10.0.2.3
```
to the top of that file. (The address 10.0.2.3 is used by the slirp program to connect you to the nameservers used by the machine to which you've dialed up. Thus, putting 10.0.2.3 in your /etc/resolv.conf as a nameserver is equivalent to putting the IP address of at least one MIT nameserver there.)

That's pretty much it. If you become root and give the command "mit1-up", it should dial MIT and start up your PPP connection. You can bring down the connection (as root) with the command "mit-down".

If you don't want to have to become root to do this, then either look into the sudo command (so that you can just give the commands "sudo mit1-up" and "sudo mit-down"), or else set the pppd suid to root, which should make this doable by any user of your machine.

The scripts

Here's the text of mit1-up:

#!/bin/sh 


(/usr/sbin/pppd connect '/usr/sbin/chat  \
  -f /etc/ppp/chat-mit1'\
 /dev/modem 115200 defaultroute -detach modem lock\
 crtscts )&

Here's the text of chat-mit1:

'ABORT' 'BUSY'
'ABORT' 'ERROR'
'ABORT' 'NO CARRIER'
'ABORT' 'NO DIALTONE'
'ABORT' 'Invalid Login'
'ABORT' 'Login incorrect'
'' 'ATZ'
'SAY' '\nDialing MIT at 1-617-258-7179...\n'
'OK' 'ATDT1-617-258-7179'
'CONNECT' ''
'SAY' '\nLogging in...\n'
#
#
# The following line waits for your login prompt
# and then send your username.  It should look like
# 'ogin:--ogin:' 'USERNAME'
'ogin:--ogin:' 'USERNAME'
#
#
# The following line waits for the password prompt
# and then sends your password.  It should look like
# 'sword:' '\qPASSWORD'
# That \q before your actual password tells the chat progrm
# that it should *not* echo your password to any logging
# facility that might be active (for debugging, etc.):
'ord:' '\qPASSWORD'
'SAY' '\nWaiting to set terminal type...\n'
'erminal--erminal' 'vt100'
'SAY' '\nWaiting for command prompt...\n'
#
#
# The following line needs to wait for your command prompt
# and then send the command 'slirp -P'.  Since my command
# prompt is the tilde character "~", I have that line as
# '~' 'slirp -P'
# If you have some other character as your command prompt,
# e.g., the percent character '%', then you should change it to
# '%' 'slirp -P'
'~' 'slirp -P'
'Ready' '\c'
'SAY' '\nSlirp is running.\n'

Here's the text of mit-down:

#! /bin/sh

echo Bringing down connection to mit...
set `ps aux|grep pppd|grep -v grep` 
kill $2 
echo "...done"

Email me: psh@math.mit.edu
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