Remote login via modem

[Ian Smith]

On Sat, 19 May 2007 12:45:35 -0700 Lou Katz <lou at metron.com> wrote:
 > On Sat, May 19, 2007 at 07:49:46AM +0200, Nikola Lecic wrote:

Sorry Nicola, no cc, your email address wasn't quoted ..

 > > On Sat, 19 May 2007 11:49:47 +1000
 > > Ivan Carey <ivan at careytech.com.au> wrote:
 > > 
 > > > Hello,
 > > > I would like to be able to access my network remotely via modem
 > > > access.
 > > > 
 > > > What I am trying to achieve is this. At the office I have a server,
 > > > this server is Not connected to the Internet, I need to be able to
 > > > Administer it from my Home office, so I am thinking that I need to
 > > > access it via a serial modem.
 > > > What do I need to do to achieve this.
 > > 
 > > You need getty(8) or /usr/ports/comms/mgetty+sendfax. Please read
 > > 
 > >   http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/dialup.html
 > >   http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/userppp.html

 > This shows how to connect to some other ISP with ppp. I need to setup MY machine
 > to accept INCOMING PPP, and can't find any doc (though I could have overlooked it).
 > Pointers to setup of incoming ppp dialin greatly appreciated.

http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/userppp.html

Assuming you're using userppp rather than pppd.  The above is a useful
outline, but for some detail I include the dialup configuration from an
old server here.  Note this was for FreeBSD 2.2.6 and a few things have
changed, like the names of ttydX and cuaaX, but maybe it'll help.

/etc/ttys:

[.. normal stuff, then ..]
# dialout: cuaa0 used by ppp
ttyd0   "/usr/libexec/getty std.57600"  vt100   off insecure
# dialups:
ttyd1   "/usr/local/sbin/mgetty"        vt100   on insecure
ttyd2   "/usr/local/sbin/mgetty"        vt100   on insecure
ttyd3   "/usr/local/sbin/mgetty"        vt100   on insecure

/usr/local/etc/mgetty+sendfax/login.config:

# ppp logs in (utmp) once authenticated
/AutoPPP/ -     -       /etc/ppp/ppp-pap-dialup @
#
#% 4/9/4 deny all members for direct (non-ppp, terminal) logins except ..
smithi  smithi  smithi  /usr/bin/login @
greg    greg    greg    /usr/bin/login @
*       -       -       /usr/bin/false @

/usr/local/etc/mgetty+sendfax/mgetty.config:

port ttyd1
debug 4
fax-id 00 00 000000
speed 115200
switchbd 19200
direct NO
blocking NO
port-owner uucp
port-group dialer
port-mode 0660
toggle-dtr YES
toggle-dtr-waittime 400
data-only yes
fax-only NO
modem-type data
# Spirit 336L (Rockwell chipset)
init-chat "" ATS0=0Q0&D2&C1S95=47 OK
modem-check-time 600
rings 2
answer-chat "" ATA CONNECT \c \r
answer-chat-timeout 60
autobauding no
ringback NO
ringback-time 30
ignore-carrier false
issue-file /etc/issue
prompt-waittime 500
login-prompt @ login:
login-time 60
diskspace 2048
notify faxadmin
fax-owner uucp
fax-group dialer
fax-mode 0660

port ttyd2
[.. ditto; port ttyd3 ditto, modulo init-chat for other type modems ..]

/etc/ppp/ppp-pap-dialup:

#!/bin/sh
#% ppp-pap-dialup 28Jun98, test version, adapted from:
#  ppp-shell 25May98 smithi from 2.2.5 handbook, PPP Configuration
IDENT=`echo $0 | sed -e 's/^.*-\(.*\)$/\1/'`
# CALLEDAS="$IDENT"
TTY=`tty`
IDENT=`basename $TTY`
/usr/sbin/ppp -direct pap$IDENT

/etc/ppp/ppp.conf:

default:
  allow users *
  enable throughput
  set log phase chat connect carrier link ipcp ccp ID0 TUN
  set speed 115200
  disable lqr
  deny lqr
  set timeout 1200

# dialout line: (4Jul98) =============================================

telstra:
  set log +command
  allow users root smithi greg
  allow mode auto ddial dedicated background
  set server 3000
  set device /dev/cuaa0
  set timeout 0
# rest of dialout config not shown ..

# dialup lines: =============================================

papttyd1:
  set server 3001
  allow users *
# force use of pap, use /etc/passwd auth
  enable pap
  enable passwdauth
# for broken linux pppd callers :(
  disable pred1
  deny pred1
  disable deflate
  deny deflate
#
  set ifaddr x.y.z.145 x.y.z.161 255.255.255.255
  delete ALL
# 1may99 keepalive filters
  set afilter 0 deny icmp
  set afilter 1 deny tcp dst eq 110
  set afilter 2 deny tcp src eq 110
# [.. various others ..]
  set afilter 15 deny udp src eq 53
  set afilter 16 deny udp dst eq 53
# last allowed is rule 19
  set afilter 17 permit 0/0 0/0

papttyd2:
  set server 3002
  allow users *
# [.. ditto ..]
  set ifaddr x.y.x.146 x.y.z.162 255.255.255.255
  delete ALL

# [ ditto papttyd3: ..]

Cheers, Ian