Study Guide Questions With Solutions
An extension will be allowed up to 25 attempts (default) for authenticating
successfully, after what it will be blacklisted for the default blacklisting interval of
1800 minutes. - ANSWER -False
The 3CX SIP port should be filtered by firewall ACL rules to maximize security
and allow only trusted IPs to reach it (VoIP providers or STUN extensions if any).
- ANSWER -True
SRTP will secure calls so that a middle-man can't see the SIP traffic in plain-text. -
ANSWER -False
CID and DID "Inbound Rules" can both be configured to route calls differently
depending on the Office Hours. - ANSWER -True
"Prepend" will add digits to the end of the dialed number before sending hte call to
the destination defined in the "Route" - ANSWER -False
Your Local IP Phone loses the Registration to 3CX and you want to troubleshoot
the issue. You should start a Wireshark Capture on the 3CX Server, reboot the
phone, and then apply the Filter sip.Cseq.Method==SUBSCRIBE in order to see if
registrations are reaching 3CX. - ANSWER -False
The "Server Activity Log" will provide information for: Phone Registrations,
Gateway and SIP Trunk Interactions, All Related Calls - ANSWER -True
Each extension gets a default password which is always the same and should be
changed for more safety. - ANSWER -False
You are debugging an audio issue using wireshark by analysing the RTP streams.
While using the RTP Stream analysis tools you see that the MAX Delta of
packages from the Provider to 3CX is 8-- MS while the Max Delta for the reverse
direction is 20 Ms. The issue is located at the provider end and not 3CX end. -
ANSWER -True
, If you want to check 3CX routing of a call then only a Wireshark capture is
needed, - ANSWER -False
Knowing only the FQDN/port of 3CX and the MAC address of a phone I could
guess its provisioning URL. - ANSWER -False
An outbound call is routed through the VoIP Provider. This "Route" of the
"Outbound Rule" has "Strip Digits" set as 0 and has no values in the "Prepend"
field. A user dials 004433272020. 3CX will send the call to the provider exactly as
dialed - ANSWER -True
You can use the same VoIP Provider in all of the Outgoing Routes of a rule -
ANSWER -True
If you want to decode audio in wireshark without any plugins, your calls will need
to be using either G711A or G711U - ANSWER -True
If you want to check the internal PBX routing of a call, the most reliable way is
through the use of the Binary Log Viewer, or which you must know some
information about the call you are investigating, like the Caller ID, the time of the
call, etc. - ANSWER -True
Assume the following scenario: 3CX is connected via a site-to-site VPN with two
different buildings where remote phones have been provisioned. 3CX is on
network 192.168.9.xxx, Phones on location A are on network 192.168.3.xxx,
Phones on location B are on network 192.168.8.xxx. When a call is established,
between an extension on remote location A to an extension to remote location B,
by default 3CX will proxy the SIP and audio traffic and send it to the extensions -
ANSWER -True
Assume the following scenario: 2 Phone Systems bridged over a site-to-site VPN
connection. Phone system A on network 192.168.9.xxx, Phone System B on
network 192.168.3.xxx. The options "Supports Re-Invite" and "Supports Re-
places" are enabled on the bridge settings. When a call is established between an
extension from PBX A to an extension behind PBX B, the audio will be exchanged
directly between the 2 extensions. - ANSWER -False
When an established call from your local extension to an external number is
terminated from your IP Phone you should see a BYE being send in from the