Ну вот, не пришлось долго ждать. Продолжаю лог
Jan 1 14:54:33> DSL out of sync
Jan 1 14:54:41> DSL Carrier is down
Jan 1 14:55:02> DSL in Sync
Jan 1 14:55:11> DSL Carrier is up
Jan 1 14:55:13> PPPD Terminated Through Signal
Jan 1 14:55:13> Connection terminated.
Jan 1 14:55:13> ppp0
Jan 1 14:55:13> pppd 2.4.3 started by root, uid 0
Jan 1 14:55:13> Connect: ppp0 {--} nas0
Jan 1 14:55:13> PAP authentication succeeded
Jan 1 14:55:13> peer from calling number 00:07:EB:59:24:3E authorized
Jan 1 14:55:13> ppp0
Jan 1 14:55:13> WAN IP address YYY.YYY.YYY.YYY
Jan 1 14:55:13> PPPoE Connect with IP Address YYY.YYY.YYY.YYY
Jan 1 14:55:13> PPPoE Connection Successfully Established
Jan 1 14:55:13> PPPoE Connect with Gateway IP Address: 10.0.0.1
Jan 1 14:55:13> WAN gateway 10.0.0.1
Jan 1 14:55:13> primary DNS address 81.25.64.194
Jan 1 14:55:13> secondary DNS address 81.25.65.26
Jan 1 14:56:21> DSL out of sync
Jan 1 14:56:22> DSL in Sync
Jan 1 14:56:29> DSL out of sync
Jan 1 14:56:41> DSL Carrier is down
Jan 1 14:57:01> DSL in Sync
Jan 1 14:57:01> DSL Carrier is up
Jan 1 14:57:02> ppp0
Jan 1 14:57:04> PPPD Terminated Through Signal
Jan 1 14:57:04> Connection terminated.
Jan 1 14:57:04> pppd 2.4.3 started by root, uid 0
Jan 1 14:57:04> Connect: ppp0 {--} nas0
Jan 1 14:57:04> PAP authentication failed
Jan 1 14:57:04> Connection terminated.
Jan 1 14:57:04> pppd 2.4.3 started by root, uid 0
Jan 1 14:57:05> Connect: ppp0 {--} nas0
Jan 1 14:57:05> PAP authentication failed
Jan 1 14:57:05> Connection terminated.
Jan 1 14:57:08> pppd 2.4.3 started by root, uid 0
Jan 1 14:57:08> Connect: ppp0 {--} nas0
Jan 1 14:57:08> PAP authentication failed
Jan 1 14:57:08> Connection terminated.
Jan 1 14:57:11> pppd 2.4.3 started by root, uid 0
Jan 1 14:57:11> Connect: ppp0 {--} nas0
Jan 1 14:57:11> PAP authentication failed
Jan 1 14:57:11> Connection terminated.
Jan 1 14:57:11> pppd 2.4.3 started by root, uid 0
Jan 1 14:57:11> Connect: ppp0 {--} nas0
Jan 1 14:57:11> PAP authentication failed
Jan 1 14:57:11> Connection terminated.
Jan 1 14:57:57> DSL out of sync
Jan 1 14:58:11> DSL Carrier is down
Jan 1 14:58:26> DSL in Sync
Jan 1 14:58:31> DSL Carrier is up
Jan 1 14:58:52> DSL out of sync
Jan 1 14:59:01> DSL Carrier is down
Jan 1 14:59:23> DSL in Sync
Jan 1 14:59:31> DSL Carrier is up
Jan 1 15:00:03> DSL out of sync
Jan 1 15:00:11> DSL Carrier is down
Jan 1 15:00:48> DSL in Sync
Jan 1 15:00:51> DSL Carrier is up
Jan 1 15:43:50> DSL out of sync
Jan 1 15:44:01> DSL Carrier is down
Jan 1 15:44:20> DSL in Sync
Jan 1 15:44:21> DSL Carrier is up
Jan 1 15:47:47> System Call Error
Jan 1 15:47:47> pppd 2.4.3 started by root, uid 0
Jan 1 15:47:47> send (sendPacket)
Jan 1 15:47:47> Default Asymmetric MTU for nas0 1500
Jan 1 15:47:47> Registering protocol inspector: 0x94168224 for VCC:0x9401fa00
Jan 1 15:47:48> pppd 2.4.3 started by root, uid 0
Jan 1 15:47:48> Connect: ppp0 {--} nas0
Jan 1 15:47:48> PAP authentication succeeded
Jan 1 15:47:48> peer from calling number 00:07:EB:59:24:3E authorized
Jan 1 15:47:48> PPPoE Connect with IP Address YYY.YYY.YYY.YYY
Jan 1 15:47:48> PPPoE Connection Successfully Established
Jan 1 15:47:48> PPPoE Connect with Gateway IP Address: 10.0.0.1
Jan 1 15:47:48> WAN IP address YYY.YYY.YYY.YYY
Jan 1 15:47:48> WAN gateway 10.0.0.1
Jan 1 15:47:48> primary DNS address 81.25.64.194
Jan 1 15:47:48> secondary DNS address 81.25.65.26
Jan 1 15:47:48> ppp0
Снова хронология моих действий по времени лога:
около 14:00 - выключил на компе соединение по локальной сети, дабы случайно не залезть в интернет и сохранить чистоту эксперимента
15:44 - включил соединение по локальной сети, инета нет, Status: Not Connected
подождал до 15:47:47, пытаясь открыть сайт в браузере
15:47:47 - нажал кнопку Connect, инет включился моментально.
Как видно из логов, в определенный момент (14:57:04) связь рвётся и провайдер некоторое время не принимает мой пароль (который я, разумееется, не менял). Почему - вопрос, конечно к провайдеру, скорее всего временные неполадки на его стороне. Происходит 5 неудачных попыток модема залогинится и после этого ничего не происходит.
Вывод - настройка Connection Setting: Always ON перестаёт работать. Приходится ручками нажимать кнопку Connect.