asp.net ean 13

asp.net ean 13

asp.net ean 13

asp.net ean 13

asp.net ean 13

asp.net ean 13,

asp.net ean 13,
asp.net ean 13,

asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,

asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,

asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,
asp.net ean 13,

I am now going to create an iptables configuration for a bastion host, kitten. I will start by describing the bastion host I intend to firewall. The host has two IP addresses: 220.240.52.228, which is bound to eth0 and is the link to the Internet, and 192.168.0.100, which is bound to interface eth1 and is a link to the internal network. I want to allow SMTP traffic in and out because the bastion host is a mail server, including relaying e-mail to the internal network SMTP server. I want to allow DNS traffic in and out because the bastion host is also a DNS server, including sending zone transfers to the internal DNS servers. I want to allow NTP traffic in and out, both over the Internet and into the internal network, as the bastion host will be the local NTP server and provide a time source for internal hosts. The host is administered using SSH, so I need to allow incoming SSH traffic from the internal network only. First let s get a start by flushing the existing rules and setting the default policies. First flush the existing rules. kitten# iptables -F Then add the default policies. I will set all the chains to DROP all traffic by default. kitten# iptables -P INPUT DROP kitten# iptables -P OUTPUT DROP kitten# iptables -P FORWARD DROP Then you want to allow access to traffic on the loopback host, lo. This is the internal 127.0.0.1 address of the host, and in order for the host to correctly function, you need to allow all traffic in and out on this interface. You can see the rules for this in Listing 2-20. Listing 2-20. Enabling Loopback Traffic kitten# iptables -A INPUT -i lo -j ACCEPT kitten# iptables -A OUTPUT -o lo -j ACCEPT

Enter the following code in Program.cs s Main() method to instantiate our service: ServiceHost MyServiceHost = new ServiceHost(typeof(7.ConfiglessService.Service1), new Uri("http://localhost:8888/7")); MyServiceHost.Open(); Console.WriteLine("Service running..."); Console.ReadLine(); MyServiceHost.Close();

I will first handle the traffic to the services running on the bastion host. Start with the SMTP traffic. You want incoming and outgoing new and established SMTP traffic to be allowed on the bastion host on the Internet interface, eth0. This allows remote SMTP servers to connect to the local SMTP server and allows the local server to connect to remote servers. You achieve this using the rules in Listing 2-21.

Listing 2-21. The External SMTP Rules kitten# --state kitten# --state iptables -A INPUT -i eth0 -p tcp --dport smtp -m state NEW,ESTABLISHED - j ACCEPT iptables -A OUTPUT -o eth0 -p tcp --sport smtp -m state NEW,ESTABLISHED -j ACCEPT

But you also want the internal SMTP server at 192.168.0.20 to be able to send mail to the bastion host and receive e-mail from it. So set up some SMTP rules for the internal 192.168.0.100 IP address, which is bound to interface eth1 to handle this incoming and outgoing SMTP traffic. These rules are in Listing 2-22. Listing 2-22. The Internal SMTP Rules kitten# iptables -m state --state kitten# iptables -m state --state -A INPUT -i eth1 -p tcp -s 192.168.0.20 --sport smtp NEW,ESTABLISHED -j ACCEPT -A OUTPUT -o eth1 -p tcp -d 192.168.0.20 --dport smtp NEW,ESTABLISHED -j ACCEPT

Now right-click on 7.ConfiglessHost in Solution Explorer and set it as the startup project, then press F5 to run the application. You should now have a running service without any configuration file.

Next you want to handle DNS traffic. You have two types of traffic, external traffic to and from the Internet and internal traffic including zone transfers to and from the internal DNS servers at 192.168.0.10 and 192.168.0.11. I have allowed new DNS queries into and out of the Internet-facing interface in Listing 2-23. Listing 2-23. The External DNS Rules kitten# --state kitten# --state kitten# --state kitten# --state iptables -A INPUT -i eth0 -p udp --dport domain -m state NEW,ESTABLISHED -j ACCEPT iptables -A INPUT -i eth0 -p tcp --dport domain -m state NEW,ESTABLISHED -j ACCEPT iptables -A OUTPUT -o eth0 -p udp --sport domain -m state NEW,ESTABLISHED -j ACCEPT iptables -A OUTPUT -o eth0 -p tcp --sport domain -m state NEW,ESTABLISHED -j ACCEPT