ubuntu 无线网的设置 /etc/ppp/options

列出几个比较重要的参数：

# If this option is given, pppd will presume the peer to be dead if n
# LCP echo-requests are sent without receiving a valid LCP echo-reply.
# If this happens, pppd will terminate the connection.  Use of this
# option requires a non-zero value for the lcp-echo-interval parameter.
# This option can be used to enable pppd to terminate after the physical
# connection has been broken (e.g., the modem has hung up) in
# situations where no hardware modem control lines are available.

lcp-echo-failure 4

# If this option is given, pppd will send an LCP echo-request frame to the
# peer every n seconds. Normally the peer should respond to the echo-request
# by sending an echo-reply. This option can be used with the
# lcp-echo-failure option to detect that the peer is no longer connected.

lcp-echo-interval 30

# Specifies how many seconds to wait before re-initiating the link after
# it terminates.  This option only has any effect if the persist or demand
# option is used.  The holdoff period is not applied if the link was
# terminated because it was idle.

holdoff 0