missing ice entries (tcp)

[ispysoftware]

I'm having a problem connecting to the webrtc server over the network from (possibly incidentally) osx devices - locally it works ok. I have existing code using googles webrtc engine and it generates more remote candidates than SIPSorcery (I have X_ICEIncludeAllInterfaceAddresses set to true)

This is the google generated candidate list (7):

0: {sdp_mid: '0', sdp: 'candidate:2700940188 1 udp 2122260223 192.168.0.50…812 typ host generation 0 ufrag xu4B network-id 1', sdp_mline_index: 0}
1: {sdp_mid: '0', sdp: 'candidate:1175178625 1 udp 2122194687 172.31.128.1…813 typ host generation 0 ufrag xu4B network-id 4', sdp_mline_index: 0}
2: {sdp_mid: '0', sdp: 'candidate:3205790974 1 udp 2122129151 172.27.32.1 …814 typ host generation 0 ufrag xu4B network-id 5', sdp_mline_index: 0}
3: {sdp_mid: '0', sdp: 'candidate:1458399816 1 udp 1686052607 124.187.106.… rport 59812 generation 0 ufrag xu4B network-id 1', sdp_mline_index: 0}
4: {sdp_mid: '0', sdp: 'candidate:4001296236 1 tcp 1518280447 192.168.0.50…type passive generation 0 ufrag xu4B network-id 1', sdp_mline_index: 0}
5: {sdp_mid: '0', sdp: 'candidate:143143281 1 tcp 1518214911 172.31.128.1 …type passive generation 0 ufrag xu4B network-id 4', sdp_mline_index: 0}
6: {sdp_mid: '0', sdp: 'candidate:4053237774 1 tcp 1518149375 172.27.32.1 …type passive generation 0 ufrag xu4B network-id 5', sdp_mline_index: 0}

the sipsorcery list is only 3:

0: {sdp_mid: '0', sdp: 'candidate:2488 1 udp 2113937663 192.168.0.50 56271 typ host generation 0', sdp_mline_index: 0}
1: {sdp_mid: '0', sdp: 'candidate:2468 1 udp 2113937663 172.31.128.1 56271 typ host generation 0', sdp_mline_index: 0}
2: {sdp_mid: '0', sdp: 'candidate:2577 1 udp 2113937663 172.27.32.1 56271 typ host generation 0', sdp_mline_index: 0}

any ideas why they're not the same? all the tcp options seem to be missing - is that a config option?