How should ppp(d) in debian 7 behave when the connection is broken?

Question

linux

I decided to raise the connection with the provider on the gateway server, and switch the modem to bridge mode - play around with setting up the firewall on iptables and just study Linux. I installed ppp, set it up, do ifup ppp0 - the connection rises, there is Internet.
Further more interesting. I wanted to check how quickly the connection will be restored when disconnected: I do ping google.com and pull out the network cable from the modem. Pings stop coming, eth0 goes down (it's with allow-hotplug), ppp0 keeps going. I insert a cable - eth0 rises, pings begin to walk, ppp0 keeps. With pulling out the telephone cable from the modem, the situation repeats exactly, and, in fact, ppp0 is always up until you do an ifdown ppp0.
Tell me, is this the regular behavior of pppd or did I mess up somewhere?

Answer 1

Apparently regular.
If you want it to detect a connection failure and terminate the connection, use the lcp-echo-interval and lcp-echo-failure options: linux.die.net/man/8/pppd