//TODO check rport configuration
SipHeaderParamName rportName = new SipHeaderParamName(
RFC3261.PARAM_RPORT);
String rport = topVia.getParam(rportName);
if (rport != null && "".equals(rport)) {
topVia.removeParam(rportName);
topVia.addParam(rportName, String.valueOf(sourcePort));
}
ServerTransaction serverTransaction =
transactionManager.getServerTransaction(sipRequest);