Hi ! I would like to develop a web interface to allow users of a Linux system to do certain tasks related to their account. I decided to write the backend of the site using Python and mod_python on Apache. To authenticate the users, I thought I could use python_pam to query the PAM service. I adapted the example bundled with the module and got this: # out is the output stream used to print debug def auth(username, password, out): def pam_conv(aut, query_list, user_data): out.write("Query list: " + str(query_list) + "\n") # List to store the responses to the different queries resp = [] for item in query_list: query, qtype = item # If PAM asks for an input, give the password if qtype == PAM.PAM_PROMPT_ECHO_ON or qtype == PAM.PAM_PROMPT_ECHO_OFF: resp.append((str(password), 0)) elif qtype == PAM.PAM_PROMPT_ERROR_MSG or qtype == PAM.PAM_PROMPT_TEXT_INFO: resp.append(('', 0)) out.write("Our response: " + str(resp) + "\n") return resp # If username of password is undefined, fail if username is None or password is None: return False service = 'login' pam_ = PAM.pam() pam_.start(service) # Set the username pam_.set_item(PAM.PAM_USER, str(username)) # Set the conversation callback pam_.set_item(PAM.PAM_CONV, pam_conv) try: pam_.authenticate() pam_.acct_mgmt() except PAM.error, resp: out.write("Error: " + str(resp) + "\n") return False except: return False # If we get here, the authentication worked return True My problem is that this function does not behave the same wether I use it in a simple script or through mod_python. To illustrate this, I wrote these simple cases: my_username = "markys" my_good_password = "lalala" my_bad_password = "lololo" def handler(req): req.content_type = "text/plain" req.write("1- " + str(auth(my_username,my_good_password,req) + "\n")) req.write("2- " + str(auth(my_username,my_bad_password,req) + "\n")) return apache.OK if __name__ == "__main__": print "1- " + str(auth(my_username,my_good_password,sys.__stdout__)) print "2- " + str(auth(my_username,my_bad_password,sys.__stdout__)) The result from the script is : Query list: [('Password: ', 1)] Our response: [('lalala', 0)] 1- True Query list: [('Password: ', 1)] Our response: [('lololo', 0)] Error: ('Authentication failure', 7) 2- False but the result from mod_python is : Query list: [('Password: ', 1)] Our response: [('lalala', 0)] Error: ('Authentication failure', 7) 1- False Query list: [('Password: ', 1)] Our response: [('lololo', 0)] Error: ('Authentication failure', 7) 2- False I don't understand why the auth function does not return the same value given the same inputs. Any idea where I got this wrong ? Here is the original script, if that could help you. Thanks a lot !