[Serusers] Call from cisco GW with Nathelper ERROR: force_rtp_proxy2: can't get From tag

[opera]

Hello all,
	
	I installed ser with nathelper, the copy from CVS.
	It work well when i use cisco ATA or Xlite call to PSTN.
	ATA --> NAT --> ser + nathelper --> cisco gw (as5300) --> PSTN.
	
	But i found that call from GW to ATA have a problem. 
	The phone in ATA is ring, but have one way voice, PSTN can hear,
	but Phone in ATA not. 
	PSTN --> cisco gw (AS5300) --> ser + nathelper --> NAT --> ATA

	The Nathelper not work and with a error in log.
	"ERROR: force_rtp_proxy2: can't get From tag" 
	                                              	
	I use ethereal found the cause is that call from cisco GW not
	haven't tag in INVITE from head. like this:  
	===============================================
	From: "87654321" <sip:87654321 at 222.222.222.2>
	To: <sip:12345678 at 333.333.333.3;user=phone;phone-context=local>
	===============================================
	
	If call from ATA have a tag, and the nathelper can work.
	use ethereal get these in INVITE message.
	================================================
    From: <sip:12345678 at 333.333.333.3;user=phone>;tag=3021292464
	To: <sip:87654321 at 333.333.333.3;user=phone>
	================================================
	
	I try to change the code in nathelper.c line 1297

	"if (get_from_tag(msg, &from_tag) == -1 || from_tag.len == 0)"
	==>
	"if (get_from_tag(msg, &from_tag) == -1)"

	Then the nathelper have no error, but RTP proxy have error log
	when i start rtpproxy with "-f" i get this:
	"command syntax error"
	
	So I think rtpproxy maybe need from_tag to work, if i skip this
	it may not work.
	
	I want to know how to make them work. 
	How to change the config at cisco 5300, so it's INVITE with tag,
	or do some change both on nathelper and rtpproxy'code. 
	My cisco 5300 IOS is 12.26(a). I also do testing with 12.27(c). 
	Same result. 

	Please help me out.

    Sorry for my poor English.
	
-- 
Best regards, 				
　 opera
　　　　　　　　　　　　　　accmail at 21cn.com
　　　　　　　　　　　　　　　　　2004-12-31