Study on Security Issue in Open Source SIP Server

Session Initiation Protocol (SIP) is a core protocol for real-time communication networks, including voice over internet protocol (VoIP). In this paper, author’s ensured security for asterisk based SIP server using packet filtering firewall tools know as iptables. Rules are applied at Linux iptables on the basis of respective port numbers, allowing and disallowing particular IP address or IP addresses with subnet. To protect the SIP server from external attack rules are applied at Linux iptables for the useful protocols likes TCP, UDP, RTP and ICMP. A popular simulation software or network protocol analyzer known as Wireshark is used to illustrate how the iptables rules worked that applied for above protocols and shows the changes before and after applying rules. This paper also shows the asterisk server monitoring using the Linux kernel log files and asterisk command line interface (CLI) that shows the successful, unsuccessful SSH login sessions and web based login (HTTPS) with IP addresses list, SIP register request to the SIP server. In this paper, our present approach helps to prevent the SIP server from unauthorized access and attacks