UC-7400-LX Plus User’s Manual
Managing Communications
4-10
export PATH
echo “1” > /proc/sys/net/ipv4/ip_forward
/sbin/iptables -F
/sbin/iptables -X
/sbin/iptables -Z
/sbin/iptables -F -t nat
/sbin/iptables -X -t nat
/sbin/iptables -Z -t nat
/sbin/iptables -P INPUT ACCEPT
/sbin/iptables -P OUTPUT ACCEPT
/sbin/iptables -P FORWARD ACCEPT
/sbin/iptables -t nat -P PREROUTING ACCEPT
/sbin/iptables -t nat -P POSTROUTING ACCEPT
/sbin/iptables -t nat -P OUTPUT ACCEPT
# Step 3. Enable IP masquerade.
Dial-up Service—PPP
PPP (Point to Point Protocol) is used to run IP (Internet Protocol) and other network protocols over
a serial link. PPP can be used for direct serial connections (using a null-modem cable) over a
Telnet link, and links established using a modem over a telephone line.
Modem / PPP access is almost identical to connecting directly to a network through the
UC-7400-LX Plus’s Ethernet port. Since PPP is a peer-to-peer system, the UC-7400-LX Plus can
also use PPP to link two networks (or a local network to the Internet) to create a Wide Area
Network (WAN).
NOTE
Click on the following links for more information about ppp:
The pppd daemon is used to connect to a PPP server from a Linux system. For detailed
information about pppd see the man page.
Example 1: Connecting to a PPP server over a simple dial-up connection
The following command is used to connect to a PPP server by modem. Use this command for old
ppp servers that prompt for a login name (replace username with the correct name) and password
(replace password with the correct password). Note that debug and defaultroute 192.1.1.17 are
optional.
#pppd connect ‘chat -v “ “ ATDT5551212 CONNECT “ “ ogin: username word: password’
/dev/ttyM0 115200 debug crtscts modem defaultroute
If the PPP server does not prompt for the username and password, the command should be entered
as follows. Replace
username
with the correct username and replace
password
with the correct
password.
#pppd connect ‘chat -v “ “ ATDT5551212 CONNECT“ “‘user username password password
/dev/ttyM0 115200 crtscts modem
The pppd options are described below:
connect ‘chat etc...’
This option gives the command to contact the PPP server. The ‘chat’ program is used to dial a
