Sponsored Content
Special Forums Cybersecurity please help to verify the simple firewall rules is ok for the call testing of my VOIP telephony syst Post 302688631 by qiubosu on Sunday 19th of August 2012 09:09:58 PM
Old 08-19-2012
please help to verify the simple firewall rules is ok for the call testing of my VOIP telephony syst

Dear Sir,

I want to test the VOIP Telephony system installed in a IP PBX server behind a NAT router. This NAT router connects to a modem (with NAT as well), and then the modem (with static public IP assigned by the ISP, e.g. 219.45.67.80) directly connects to the Internet. There are several IP phones connect to the IP PBX server. The NAT router is configured as DHCP, and as a gateway (e.g. 192.168.3.1) also for the LAN (the NAT router, the IP PBX server and the IP phones consist this LAN). The IP PBX server and the IP phones all connect to the ports of the NAT router, and are with static local IP addresses (e.g. 192.168.3.10, 192.168.3.11, 192.168.3.12, 192.168.3.13 etc). This is the setup of the VOIP telephony system.

I want to make inbound and outbound VOIP phone calls to test the VOIP telephony system. For security, I need to setup the firewall in the IP PBX server (192.168.3.10). But to make it simple as a start (and make it more and more complicated when the simple one works), I plan to just add very simple rules to accept all the incoming and outgoing traffics between Internet and the IP PBX server (192.168.3.10), and forward all the traffic from this IP PBX server (192.168.3.10) to the IP phones (192.168.3.11, 192.168.3.12, 192.168.3.13). The purpose to make the firewall in the IP PBX server as simple as possible is to avoid the possibility that the inappropriate configuration of the IP PBX server firewall lead to the VOIP phone calls failed (there are other reasons could make the VOIP phone calls failed also, e.g. the inappropriate configuration of IP PBX server and the inappropriate of IP phones ......), then I can narrow down the root cause to make the VOIP phone calls failed.

Below is the simple firewall I want to setup in the IP PBX server, i.e. accept and incoming and outgoing traffics, and forward all traffics to IP phones, without specifying any source and destination IP addresses and ports. It is much appreciated if you can help to verify whether this simple firewall rules are ok for my purpose.

#!/bin/sh

# Wipe the tables clean
iptables -F

# INPUT SIDE
iptables -A INPUT -j ACCEPT

# Output side
iptables -A OUTPUT -j ACCEPT

# FORWARD SIDE
iptables -A FORWARD -j ACCEPT
 

8 More Discussions You Might Find Interesting

1. Post Here to Contact Site Administrators and Moderators

Simple rules of the UNIX.COM forums:

(1) No flames, shouting (all caps), sarcasm, bullying or arrogant posts. (2) No negative comments about others or unpolite remarks. Be patient. (3) Refrain from idle chatter that does not contribute to the knowledge base. (4) Do not 'bump up' questions if they are not answered... (0 Replies)
Discussion started by: Neo
0 Replies

2. UNIX for Advanced & Expert Users

Firewall - 2 Internet accesses - routing rules from source

Hello, I would like to modify my firewall configuration for being able to handle 2 internet connections in my Red zone. I would then like to configure some selecting routing rules depending on the internal source. Actual configuration: ===================== 1 router A (ISP)... (1 Reply)
Discussion started by: el70
1 Replies

3. Shell Programming and Scripting

Please verify the simple Shell code

Hi, i am trying to write script which will delete files(more than 90 days older) from different directories. Please check its ok if i implement it in SUN solaris10; One important thing i used here "exec" flag. I heard from someone- as i have lots of files "exec" flag may give error like too... (2 Replies)
Discussion started by: thepurple
2 Replies

4. UNIX for Dummies Questions & Answers

Create new simple System Call.

Hello to all! I am new with unix and i need your help to make something.. First of all i want to inform you that i am working under the Minix 3 OS. What i want to make is, a new system call in terms of the process manager. This system call should take an integer as a parameter (input) and... (1 Reply)
Discussion started by: kostis1904
1 Replies

5. Red Hat

Iptables/Firewall rules for multicast IP.

Hi Gurus, I need to add Multicast Port = xyz Multicast Address = 123.134.143 ( example) to my firewall rules. Can you please guide me with the lines I need to update my iptables files with. (0 Replies)
Discussion started by: rama krishna
0 Replies

6. UNIX for Dummies Questions & Answers

I have firewall rules to open ports, why telnet refuses connection?

Alright... this question comes from the fact that I'm trying to setup postfix to relay messages to Office 365 SMTP but its giving me connection refused... I read that if you have doubts if your port is open or not you should telnet to them so thats what I did. This is a Red Hat 6.3 box. My... (4 Replies)
Discussion started by: RedSpyder
4 Replies

7. UNIX for Beginners Questions & Answers

Simple rules of the UNIX.COM forums:

RULES OF THE UNIX AND LINUX FORUMS For the latest version of the community rules (the official community rules page), please visit here. No flames, shouting (all caps), sarcasm, bullying, profanity or arrogant posts. No negative comments about others or impolite remarks. Be patient. No... (1 Reply)
Discussion started by: Neo
1 Replies

8. Shell Programming and Scripting

Consolidate several lines of a CSV file with firewall rules, in order to parse them easier?

Consolidate several lines of a CSV file with firewall rules Hi guys. I have a CSV file, which I created using an HTML export from a Check Point firewall policy. Each rule is represented as several lines, in some cases. That occurs when a rule has several address sources, destinations or... (4 Replies)
Discussion started by: starriol
4 Replies
PPTPD.CONF(5)							File Formats Manual						     PPTPD.CONF(5)

NAME
pptpd.conf - PPTP VPN daemon configuration DESCRIPTION
pptpd(8) reads options from this file, usually /etc/pptpd.conf. Most options can be overridden by the command line. The local and remote IP addresses for clients must come from the configuration file or from pppd(8) configuration files. OPTIONS
option option-file the name of an option file to be passed to pppd(8) in place of the default /etc/ppp/options so that PPTP specific options can be given. Equivalent to the command line --option option. stimeout seconds number of seconds to wait for a PPTP packet before forking the pptpctrl(8) program to handle the client. The default is 10 seconds. This is a denial of service protection feature. Equivalent to the command line --stimeout option. debug turns on debugging mode, sending debugging information to syslog(3). Has no effect on pppd(8) debugging. Equivalent to the command line --debug option. bcrelay internal-interface turns on broadcast relay mode, sending all broadcasts received on the server's internal interface to the clients. Equivalent to the command line --bcrelay option. connections n limits the number of client connections that may be accepted. If pptpd is allocating IP addresses (e.g. delegate is not used) then the number of connections is also limited by the remoteip option. The default is 100. delegate delegates the allocation of client IP addresses to pppd(8). Without this option, which is the default, pptpd manages the list of IP addresses for clients and passes the next free address to pppd. With this option, pptpd does not pass an address, and so pppd may use radius or chap-secrets to allocate an address. localip ip-specification one or many IP addresses to be used at the local end of the tunnelled PPP links between the server and the client. If one address only is given, this address is used for all clients. Otherwise, one address per client must be given, and if there are no free addresses then any new clients will be refused. localip will be ignored if the delegate option is used. remoteip ip-specification a list of IP addresses to assign to remote PPTP clients. Each connected client must have a different address, so there must be at least as many addresses as you have simultaneous clients, and preferably some spare, since you cannot change this list without restarting pptpd. A warning will be sent to syslog(3) when the IP address pool is exhausted. remoteip will be ignored if the dele- gate option is used. noipparam by default, the original client IP address is given to ip-up scripts using the pppd(8) option ipparam. The noipparam option pre- vents this. Equivalent to the command line --noipparam option. listen ip-address the local interface IP address to listen on for incoming PPTP connections (TCP port 1723). Equivalent to the command line --listen option. pidfile pid-file specifies an alternate location to store the process ID file (default /var/run/pptpd.pid). Equivalent to the command line --pidfile option. speed speed specifies a speed (in bits per second) to pass to the PPP daemon as the interface speed for the tty/pty pair. This is ignored by some PPP daemons, such as Linux's pppd(8). The default is 115200 bytes per second, which some implementations interpret as meaning "no limit". Equivalent to the command line --speed option. NOTES
An ip-specification above (for the localip and remoteip tags) may be a list of IP addresses (for example 192.168.0.2,192.168.0.3), a range (for example 192.168.0.1-254 or 192.168.0-255.2) or some combination (for example 192.168.0.2,192.168.0.5-8). For some valid pairs might be (depending on use of the VPN): localip 192.168.0.1 remoteip 192.168.0.2-254 or localip 192.168.1.2-254 remoteip 192.168.0.2-254 ROUTING CHECKLIST - PROXYARP Allocate a section of your LAN addresses for use by clients. In /etc/ppp/options.pptpd. set the proxyarp option. In pptpd.conf do not set localip option, but set remoteip to the allocated address range. Enable kernel forwarding of packets, (e.g. using /proc/sys/net/ipv4/ip_forward ). The server will advertise the clients to the LAN using ARP, providing it's own ethernet address. bcrelay(8) should not be required. ROUTING CHECKLIST - FORWARDING Allocate a subnet for the clients that is routable from your LAN, but is not part of your LAN. In pptpd.conf set localip to a single address or range in the allocated subnet, set remoteip to a range in the allocated subnet. Enable kernel forwarding of packets, (e.g. using /proc/sys/net/ipv4/ip_forward ). The LAN must have a route to the clients using the server as gateway. The server will forward the packets unchanged between the clients and the LAN. bcrelay(8) will be required to support broadcast protocols such as NETBIOS. ROUTING CHECKLIST - MASQUERADE Allocate a subnet for the clients that is not routable from your LAN, and not otherwise routable from the server (e.g. 10.0.0.0/24). Set localip to a single address in the subnet (e.g. 10.0.0.1), set remoteip to a range for the rest of the subnet, (e.g. 10.0.0.2-200). Enable kernel forwarding of packets, (e.g. using /proc/sys/net/ipv4/ip_forward ). Enable masquerading on eth0 (e.g. iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE ). The server will translate the packets between the clients and the LAN. The clients will appear to the LAN as having the address corre- sponding to the server. The LAN need not have an explicit route to the clients. bcrelay(8) will be required to support broadcast proto- cols such as NETBIOS. FIREWALL RULES
pptpd(8) accepts control connections on TCP port 1723, and then uses GRE (protocol 47) to exchange data packets. Add these rules to your iptables(8) configuration, or use them as the basis for your own rules: iptables --append INPUT --protocol 47 --jump ACCEPT iptables --append INPUT --protocol tcp --match tcp --destination-port 1723 --jump ACCEPT SEE ALSO
pppd(8), pptpd(8), pptpd.conf(5). 29 December 2005 PPTPD.CONF(5)
All times are GMT -4. The time now is 02:15 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy