Disclaimer: I know I should not be using chan_sip

That being said I am trying to force Asterisk to use tcp by doing Dial(SIP/1234::::tcp@1.1.1.1//2.2.2.2)

I want that Asterisk should send out the packet using TCP via the SIP proxy
2.2.2.2. When I do a debug I see Asterisk using UDP. Is this because I am using a SIP proxy?