Callback – это звонок с обратным вызовом т.е. когда оператор связи устанавливает соединение с абонентом, таким образом исключив из расходов абонента стоимость за исходящее от абонента телефонное соединение. Подключение производится в два этапа:
Номер абонента, на который необходимо перезвонить : логин
Пример:
5409652:testlogin
Пример конфигурации сервера доступа Cisco 2511 для организации Callback:
!
chat-script offhook "" "ATH1" OK
chat-script callback ABORT ERROR ABORT BUSY "" "ATZ" OK "AT" OK "ATDT \T" TIMEOUT 60 CONNECT \c
!
!
interface Group-Async1
ip unnumbered Ethernet0
encapsulation ppp
no ip route-cache
async mode interactive
peer default ip address pool TEST
ppp callback accept
ppp authentication pap
group-range 1 15
!
!
line 1
script modem-off-hook offhook
script callback callback
modem InOut
modem autoconfigure type usr_sportster
transport input all
autoselect ppp
speed 115200
!
Для проверки работоспособности данной схемы необходимо анализировать журнал событий радиус-сервера и сервера доступа.
Пример журнала событий радиус-сервера:
?Debug : Oct 24 19:31:19 RADIUS Auth: Auth scheme: PAP
?Debug : Oct 24 19:31:19 RADIUS Auth: PAP: <1> vs <1>
?Debug : Oct 24 19:31:19 RADIUS Auth: PAP: Authorized user <d>
?Debug : Oct 24 19:31:19 RADIUS Auth: Callback for link <1> enabled. Login <d> callback number <203>
?Debug : Oct 24 19:31:19 RADIUS Auth: Settings callback number into Access-Accept packet
Пример журнала событий сервера доступа Cisco 2511:
Oct 24 13:35:32 10.1.2.95 760: *Jul 30 05:54:28.219: RADIUS(0000000B): Send Access-Request to 10.1.2.137:1812 id 1645/6, len 8
2
Oct 24 13:35:32 10.1.2.95 761: *Jul 30 05:54:28.223: RADIUS: authenticator 54 39 F6 77 4D 25 C6 EB - 18 AA D4 2D FC 44 B5 D6
Oct 24 13:35:32 10.1.2.95 762: *Jul 30 05:54:28.227: RADIUS: Framed-Protocol [7] 6 PPP [1]
Oct 24 13:35:32 10.1.2.95 763: *Jul 30 05:54:28.227: RADIUS: User-Name [1] 7 "203:d"
Oct 24 13:35:32 10.1.2.95 764: *Jul 30 05:54:28.231: RADIUS: User-Password [2] 18 *
Oct 24 13:35:32 10.1.2.95 765: *Jul 30 05:54:28.235: RADIUS: NAS-Port-Type [61] 6 Async [0]
Oct 24 13:35:32 10.1.2.95 766: *Jul 30 05:54:28.235: RADIUS: Calling-Station-Id [31] 7 "async"
Oct 24 13:35:32 10.1.2.95 767: *Jul 30 05:54:28.239: RADIUS: NAS-Port [5] 6 1
Oct 24 13:35:32 10.1.2.95 768: *Jul 30 05:54:28.243: RADIUS: Service-Type [6] 6 Framed [2]
Oct 24 13:35:32 10.1.2.95 769: *Jul 30 05:54:28.243: RADIUS: NAS-IP-Address [4] 6 10.1.2.95
Oct 24 13:35:32 10.1.2.95 770: *Jul 30 05:54:28.255: RADIUS: Received from id 1645/6 10.1.2.137:1812, Access-Accept, len 25
Oct 24 13:35:32 10.1.2.95 771: *Jul 30 05:54:28.259: RADIUS: authenticator B0 7D 87 DF FC A5 1D 49 - EA 3E D5 04 51 A3 AC 21
Oct 24 13:35:32 10.1.2.95 772: *Jul 30 05:54:28.263: RADIUS: Callback-Number [19] 5 "203"
Oct 24 13:35:32 10.1.2.95 773: *Jul 30 05:54:28.271: RADIUS(0000000B): Received from id 1645/6
Oct 24 13:35:32 10.1.2.95 774: *Jul 30 05:54:28.287: APPP1: Output packet, len = 9, header = FF 3 C0 23
Oct 24 13:35:32 10.1.2.95 775: *Jul 30 05:54:28.291: APPP1: Output packet, len = 11, header = FF 3 C0 29
Oct 24 13:35:32 10.1.2.95 776: *Jul 30 05:54:28.483: APPP1: Input packet, len = 9, header = C0 29 2 1
Oct 24 13:35:32 10.1.2.95 777: *Jul 30 05:54:28.531: APPP1: Output packet, len = 11, header = FF 3 C0 29
Oct 24 13:35:32 10.1.2.95 778: *Jul 30 05:54:28.707: APPP1: Input packet, len = 20, header = FF 3 C0 21
Oct 24 13:35:32 10.1.2.95 779: *Jul 30 05:54:28.711: APPP1: Output packet, len = 8, header = FF 3 C0 21
Oct 24 13:35:33 10.1.2.95 780: *Jul 30 05:54:28.739: TTY1 Callback PPP process creation
Oct 24 13:35:33 10.1.2.95 781: *Jul 30 05:54:28.743: TTY1 Callback process initiated, user: dialstring 203
Oct 24 13:35:33 10.1.2.95 782: *Jul 30 05:54:29.743: TTY1: Async Int reset: Dropping DTR
Oct 24 13:35:36 10.1.2.95 783: *Jul 30 05:54:31.743: %LINK-5-CHANGED: Interface Async1, changed state to reset
Oct 24 13:35:39 10.1.2.95 784: *Jul 30 05:54:34.743: Async1: Async protocol mode stopped for 0.0.0.0
Oct 24 13:35:39 10.1.2.95 785: *Jul 30 05:54:34.751: TTY1 Callback forced wait = 4 seconds
Oct 24 13:35:41 10.1.2.95 786: *Jul 30 05:54:36.747: %LINK-3-UPDOWN: Interface Async1, changed state to down
Oct 24 13:35:41 localhost kernel: Oct 24 13:35:41 10.1.2.95 786: *Jul 30 05:54:36.747: %LINK-3-UPDOWN: Interface Async1, chang
ed state to down
Oct 24 13:35:43 10.1.2.95 787: *Jul 30 05:54:38.755: CHAT1: Asserting DTR