随着搜索研究的深入, 发现上面提到的方法可能只能解决那个问题中特别的罗技sip设备的问题, 但其它sip设备可能仍然有问题. 看到这里的报告:
http://forums.dlink.com/index.php?topic=7616.0
还有这里:
http://www.junctionnetworks.com/knowledgebase/onsip/devices/router-configuration/d-link-no-not-purchase-until-further-notice-firmwa-0
"Please note that firmware 3.x is incompatible with our service. The 3.x DLink firmware requires that a SIP ALG be enabled in order to pass SIP packets through the router. As the SIP ALG alters the SIP packet, this requirement is incompatible with OnSIP Hosted PBX. "
要等回家试了才知道.