I have tried out Keiichi Honda's "SIP-IX" service, which does a similar numeric-prefix to SIP domain name connection service.
SIP IX -
The SIP INVITE message shown in the dial-a-spiral test shows that sipix.jp does not add the "Record-Route:" header. The SIP-IX service therefore avoids potential problems caused by "lr=on" / "lr".
"Dial-a-spiral" test:
http://forum.voxalot.com/sip-broker-....html#post9690
Code:
INVITE sip:050xxxxxxxx@xxx.xxx.xxx.xxx:5060 SIP/2.0
Record-Route: <sip:64.34.173.199;lr=on;ftag=2568014107>
Record-Route: <sip:64.34.162.221;lr=on;ftag=2568014107>
Record-Route: <sip:64.34.162.221;lr=on;ftag=2568014107>
Via: SIP/2.0/UDP 64.34.173.199;branch=z9hG4bKd728.14ebdfe4.0
Via: SIP/2.0/UDP 64.34.162.221;branch=z9hG4bKd728.bbb7b4e1.0
Via: SIP/2.0/UDP 58.158.169.93;branch=z9hG4bKd728.db54b947.0
Via: SIP/2.0/UDP 64.34.162.221;branch=z9hG4bKd728.abb7b4e1.0
Via: SIP/2.0/UDP aaa.bbb.ccc.d:6080;branch=z9hG4bK24374553867812144
...
64.34.173.199 = us.voxalot.com
64.34.162.221 = sipbroker.com
58.158.169.93 = sipix.jp
aaa.bbb.ccc.d = SIP device originating the call)