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Disable SRTP offer


duggyk
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I'm making calls whereby an INVITE without SDP is sent to PBXNSIP to initiate a call.

 

PBXNSIP always seems to respond with a 200OK containing and SDP which contains a 'crypto' line (initiating SRTP when the calling device sends an ACK which contains the SDP).

 

How can I stop PBXNSIP sending any crypto lines in SDP's (i.e. turn off SRTP) ???

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I'm making calls whereby an INVITE without SDP is sent to PBXNSIP to initiate a call.

 

PBXNSIP always seems to respond with a 200OK containing and SDP which contains a 'crypto' line (initiating SRTP when the calling device sends an ACK which contains the SDP).

 

How can I stop PBXNSIP sending any crypto lines in SDP's (i.e. turn off SRTP) ???

 

There is no option. This behavior is neccessary because there are (buggy) user-agents out there which offer SRTP keys over insecure transport layer and if the PBX does not answer the crypto-line in a response then the call would not establish.

 

A UA that does not support SRTP should silently ignore this.

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There is no option. This behavior is neccessary because there are (buggy) user-agents out there which offer SRTP keys over insecure transport layer and if the PBX does not answer the crypto-line in a response then the call would not establish.

 

A UA that does not support SRTP should silently ignore this.

 

 

Is sending cryptographic information over a non-secure transport a good idea? I see that the a=crypto lines are sent whatever the transport layer (TCP/UDP/TLS)

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There is no option. This behavior is neccessary because there are (buggy) user-agents out there which offer SRTP keys over insecure transport layer and if the PBX does not answer the crypto-line in a response then the call would not establish.

 

A UA that does not support SRTP should silently ignore this.

 

If there's no way to remove the crypto line from the SDP when using UDP or TCP connections i'll have to find an alternative solution (end of trial) :rolleyes:

 

In my case the UA isn't offering any capabilities in the initial INVITE (no SDP).

 

PBXNSIP is offering SDP in the 200OK (with crypto line even though the transport layer is UDP/TCP).

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If there's no way to remove the crypto line from the SDP when using UDP or TCP connections i'll have to find an alternative solution (end of trial) :rolleyes:

 

In my case the UA isn't offering any capabilities in the initial INVITE (no SDP).

 

PBXNSIP is offering SDP in the 200OK (with crypto line even though the transport layer is UDP/TCP).

 

Maybe we can take the insecure offer out. I believe this was for an old firmware version of a phone, today it should not be relevant any more. What OS are you on?

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