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3CX ADVANCED CERTIFICATION EXAM QUESTIONS
On outbound calls to external numbers, 3CX will process "Outbound Rules" in a "Best
Matching" way, depending on how many of the criteria match. - answer-False
Wireshark can - without any additional Plugins Decode all Codecs including G711A,
G711U, GSM, G729, G726 - answer-False
STUN extensions can be configured to connect to the tunnel port of 3CX instead of the
SIP port for more security. - answer-False
In the criteria of the "Outbound Rules", "Calls from Extension(s)" having comma
separated values will allow multiple extension ranges to be defined - answer-True
The Virtual Extension of the slave must match the master side virtual extension number
- answer-True
For extensions that are registered over multiple site-to-site VPNs, by default 3CX
delivers the audio between phones if they are on different subnets. - answer-False
The log files of 3CX are never cleaned even when you restart the 3CX Services -
answer-False
Once Secure SIP has been configured in 3CX, Secure SIP certificates will need to be
deployed manually in phones and softphones OS so that they can communicate. -
answer-False
Remote extensions may be provisioned using the HTTP or HTTPS URLs - answer-
False
The default Voicemail PIN of an extension consist of 4 random alphanumerical
characters. - answer-False
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Your 3CX has only one SIP Trunk and receives a call from number 8135791691. If you
have a "Inbound CID Reformatting" rule on the Trunk with "Source Pattern" 813(...)(.*)
and "Replace Pattern" \1\2, the extension that receives the call will see "5791691" as
the caller ID on its display. - answer-True
When 3CX has been installed without a FQDN from 3CX and in split DNS mode, the
DNS server must not be installed on the same machine as the phone system. - answer-
True
Your Local IP Phone loses the registration to 3CX and you want do troubleshoot the
issue. You should start a Wireshark Capture on the 3CX Server, reboot the phone, and
then apply the Filter sip.Cseq.Method==REGISTER in order to see if registrations are
reaching 3CX - answer-True
Your 3CX has only one SIP Trunk and receives a call from number 422033272020 and
you want it to be presented on the extension display as +44272020. You can do this
with a "Inbound CID Reformatting" rule on the Trunk with "Source Pattern" 44(..)(..)(.*)
and "Replace Pattern" +44\3. - answer-True
When selecting the option "I need a 3CX FQDN" an internal DNS is not mandatory -
answer-True
The order of "Inbound Rules" is not important when you have DID and CID "Inbound
Rules", CIDs always have higher priority. - answer-False
You have a Master Bridge with 3-digit extensions 1xxx and a Slave Bridge with 4-digit
extensions 2xxx. In the "Outbound Rules" you use to rote calls across the bridge, using
a prefix is mandatory. - answer-False
You have run the 3CX "Firewall Checker" and comes up as Green, but you still have
audio issues and calls dropping on on outbound / inbound calls. Can SIP ALG be the
culprit? - answer-True
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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
3CX ADVANCED CERTIFICATION EXAM QUESTIONS
On outbound calls to external numbers, 3CX will process "Outbound Rules" in a "Best
Matching" way, depending on how many of the criteria match. - answer-False
Wireshark can - without any additional Plugins Decode all Codecs including G711A,
G711U, GSM, G729, G726 - answer-False
STUN extensions can be configured to connect to the tunnel port of 3CX instead of the
SIP port for more security. - answer-False
In the criteria of the "Outbound Rules", "Calls from Extension(s)" having comma
separated values will allow multiple extension ranges to be defined - answer-True
The Virtual Extension of the slave must match the master side virtual extension number
- answer-True
For extensions that are registered over multiple site-to-site VPNs, by default 3CX
delivers the audio between phones if they are on different subnets. - answer-False
The log files of 3CX are never cleaned even when you restart the 3CX Services -
answer-False
Once Secure SIP has been configured in 3CX, Secure SIP certificates will need to be
deployed manually in phones and softphones OS so that they can communicate. -
answer-False
Remote extensions may be provisioned using the HTTP or HTTPS URLs - answer-
False
The default Voicemail PIN of an extension consist of 4 random alphanumerical
characters. - answer-False
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Your 3CX has only one SIP Trunk and receives a call from number 8135791691. If you
have a "Inbound CID Reformatting" rule on the Trunk with "Source Pattern" 813(...)(.*)
and "Replace Pattern" \1\2, the extension that receives the call will see "5791691" as
the caller ID on its display. - answer-True
When 3CX has been installed without a FQDN from 3CX and in split DNS mode, the
DNS server must not be installed on the same machine as the phone system. - answer-
True
Your Local IP Phone loses the registration to 3CX and you want do troubleshoot the
issue. You should start a Wireshark Capture on the 3CX Server, reboot the phone, and
then apply the Filter sip.Cseq.Method==REGISTER in order to see if registrations are
reaching 3CX - answer-True
Your 3CX has only one SIP Trunk and receives a call from number 422033272020 and
you want it to be presented on the extension display as +44272020. You can do this
with a "Inbound CID Reformatting" rule on the Trunk with "Source Pattern" 44(..)(..)(.*)
and "Replace Pattern" +44\3. - answer-True
When selecting the option "I need a 3CX FQDN" an internal DNS is not mandatory -
answer-True
The order of "Inbound Rules" is not important when you have DID and CID "Inbound
Rules", CIDs always have higher priority. - answer-False
You have a Master Bridge with 3-digit extensions 1xxx and a Slave Bridge with 4-digit
extensions 2xxx. In the "Outbound Rules" you use to rote calls across the bridge, using
a prefix is mandatory. - answer-False
You have run the 3CX "Firewall Checker" and comes up as Green, but you still have
audio issues and calls dropping on on outbound / inbound calls. Can SIP ALG be the
culprit? - answer-True
, Page 3 of 22
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
