ENUM or “peer-to-peer” IP telephony
You are now an IP telephony user and have installed an Asterisk. You are using an IP Centrex link to a SIP or IAX operator. Go to the next level with peer-to-peer telephony with ENUM.
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Volontary bug in some SIP IP phones?
When looking at the published SIP exploit over a Grandstream IP phone1, one could quickly arrive to the conclusion this was more a feature than a bug, for what purpose is the real question to be asked.
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IAX and RSA authentication
IAX is the preferred solution when interconnecting two Asterisk. In addition to voice cipher (see “IAX trunk and voice ciphering“) and secret based authentication, it could be interesting to bring the authentication to an upper level: RSA key verification.
The purpose of this article is to explain how to setup RSA authentication in IAX trunk but also how to use X.509 certificates to get RSA keys from.
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IP Centrex: using international numbers
One of the interests of IP telephony is the fact the Internet can become a network to carry telephony for some usages. We cannot consider today this network is offering a high grade quality but its ubiquity is incredible and no telco can nowadays be compared on this topic. It becomes relatively easy to imagine using a foreign ToIP operator in order to access specific prices in this country on one hand and be able to accept calls with a local number on the other hand.
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Asterisk redundancy, a very simple approach
As soon as we install in an organisation an Asterisk IP telephony service, it can impact directly on the service and we should study how it can be resilient. This article proposes a very simple but redundant telephony service with two Asterisk servers installed in a load-balancing mode.
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