我筆記本用ubuntu的時候連wifi總是掉線重連，解決的途徑是要去看/etc/ppp/下的option

ppp就是點對點協議，所有與ppp配置相關的檔案都放在這個目錄下

那就sudo vim /etc/ppp/option 吧

在兩百一十多行的地方有這樣一段

# 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 4

# 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 30
 

下面一段意思是說lcp-echo-failure這個值設了，我們的撥號客戶端pppd就會向你的peer傳送一個請求幀，然後等他回覆，lcp-echo-failure設為30也就是說如果pppd發了30次請求幀你的peer都沒有回，他就認為你的連結斷了。而上面那個lcp-echo-interval就是你每次等待回覆的時間，預設設為4，如果網不是很給力的話，很容易就超時，被認為要重連，所以就頻繁地斷連線很煩人。現在把每次等待時間改長一點，設為30，然後就不那麼容易掉了。

# 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 <span style="color:#FF0000;">30</span>

# 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 30