[Serusers] stun or nathelper module?

Hi all, I just was wondering could somebody tell me whether I should be using stun or the nathelper module or both?.... I have clients behind NAT and ser behind NAT. The ser obviously has a private address on the private lan but it should be reachable via its public address which is natted. However this is not the case and I cant get a call working. All the best, Aisling. -------------------Legal Disclaimer--------------------------------------- The above electronic mail transmission is confidential and intended only for the person to whom it is addressed. Its contents may be protected by legal and/or professional privilege. Should it be received by you in error please contact the sender at the above quoted email address. Any unauthorised form of reproduction of this message is strictly prohibited. The Institute does not guarantee the security of any information electronically transmitted and is not liable if the information contained in this communication is not a proper and complete record of the message as transmitted by the sender nor for any delay in its receipt. ----------------------------------------------------------------------------------------