Cisco SPA504G doesn't connect through TLS/SRTP

FreePBX Endpoints
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1

Hi there,

I’m trying to connect my Cisco SPA504G to my FreePBX over TLS/SRTP, but it doesn’t register: “Failed (Not Reachable)”

This is what I see in asterisk -rvvv when the phone tries to register every 30 sec

WARNING[2326]: pjproject: <?>:                       SSL SSL_ERROR_SSL (Handshake): Level: 0 err: <336027900> <SSL routines-SSL23_GET_CLIENT_HELLO-unknown protocol> len: 0

Settings applied on the Cisco phone:
SRTP method: s-descriptor
SIP Transport: TLS (with the TLS address of my FreePBX)
Secure Call: enabled

Does anybody know how to fix this?

2

“Unknown protocol” looks like a TLS version mismatch. How old is your phone’s firmware? What TLS version did you set on FreePBX?

3

The phone is running firmware version 7.6.2g, (released on Oct 28 2020) FreePBX has been set to TLS 1.2 with a Let’s Encrypt cert.

4

Yeah but I dont think the SPA504G supports TLS 1.2 and LE ripped out anything less than that last year.

The old SPA devices will not work with current TLS certs/setups.

5

Yeah, I did see on Cisco’s product page about it that it was release in 2009 and that they still support it to this day what the hecc :joy:

So… I’m now eyeballing on a Yealink SIP-T33P

6

At least that model is not EoL.

7

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