One of the problems with setting up a VoIP service with an SIP
provider is that there is no standardization. The same SIP client may
require different parameters to work with various SIP providers and
different clients will need new pieces of information to connect to the
same SIP provider.
This leads to a lot of confusion for new users who're just getting into the SIP VoIP field. A few confusing parameters which need to be set are: STUN servers, outbound proxy servers, codecs, authentication username etc. Till the time comes when all SIP clients have a standardized interface for connection to an SIP server, users like us will have to figure out for ourselves what these fields mean so that we can set them in a meaningful way. Of course, if you've obtained a hosted PBX plan, just contact your ITSP to find out how you can automatically provision your SIP client.
The outbound proxy server is a way for VoIP clients to bypass the local security settings and firewalls which may be imposed either by the network administrator or even by the ISPs. For one reason or the other, an ISP might choose to restrict VoIP calls on its network by blocking the most commonly used port - 5060. With this being inaccessible, the SIP client will be unable to initiate VoIP calls to an SIP server using regular means. We need a workaround. One way is to use what is known as a STUN server. The other is ensuring that you have an outbound proxy configured.
An outbound proxy server is merely an extra step to the SIP server. A request sent by your SIP client to the outbound proxy do not have the appearance of a VoIP call and it is the proxy itself which will actually communicate with the server and act as a go between. In many ways, this is very much like a virtual private network or a VPN - hence the name "proxy".
Of course, you might not require an outbound proxy server at all. But some SIP providers and clients mandate the inclusion of the field. This can be inconvenient if your provider doesn't give you the proper settings with which you need to configure your clients. Also if you're making use of a STUN server, you don't need to configure an outbound proxy server at all since that would just be a waste.
To find out what the settings are for your proxy, go to your provider's website and search for the information there. Or call your SIP provider and ask them to give you the details if your client or VoIP phone is not set up to be automatically configured.
This leads to a lot of confusion for new users who're just getting into the SIP VoIP field. A few confusing parameters which need to be set are: STUN servers, outbound proxy servers, codecs, authentication username etc. Till the time comes when all SIP clients have a standardized interface for connection to an SIP server, users like us will have to figure out for ourselves what these fields mean so that we can set them in a meaningful way. Of course, if you've obtained a hosted PBX plan, just contact your ITSP to find out how you can automatically provision your SIP client.
The outbound proxy server is a way for VoIP clients to bypass the local security settings and firewalls which may be imposed either by the network administrator or even by the ISPs. For one reason or the other, an ISP might choose to restrict VoIP calls on its network by blocking the most commonly used port - 5060. With this being inaccessible, the SIP client will be unable to initiate VoIP calls to an SIP server using regular means. We need a workaround. One way is to use what is known as a STUN server. The other is ensuring that you have an outbound proxy configured.
An outbound proxy server is merely an extra step to the SIP server. A request sent by your SIP client to the outbound proxy do not have the appearance of a VoIP call and it is the proxy itself which will actually communicate with the server and act as a go between. In many ways, this is very much like a virtual private network or a VPN - hence the name "proxy".
Of course, you might not require an outbound proxy server at all. But some SIP providers and clients mandate the inclusion of the field. This can be inconvenient if your provider doesn't give you the proper settings with which you need to configure your clients. Also if you're making use of a STUN server, you don't need to configure an outbound proxy server at all since that would just be a waste.
To find out what the settings are for your proxy, go to your provider's website and search for the information there. Or call your SIP provider and ask them to give you the details if your client or VoIP phone is not set up to be automatically configured.
