This article describes how to use iptables to implement packet filtering and configure Network Address Translation (NAT), with specific reference to the information needed for the RHCE EX300 certification exam.
Remember, the exams are hands-on, so it doesn’t matter which method you use to achieve the result, so long as the end product is correct. Continue reading
Most of the time routing will be done by your network hardware, but it can be done using Linux.
This article provides an introduction to routing IP traffic on Linux, with specific reference to the information needed for the RHCE EX300 certification exam.
Remember, the exams are hands-on, so it doesn’t matter which method you use to achieve the result, so long as the end product is correct. Continue reading
This article describes the installation and configuration of a HTTP server on Linux, with specific reference to the information needed for the RHCE EX300 exam. Continue reading
Firewalls are set-up primarily to filter and/or enhance packets which pass through the network. When a packet arrives at a firewall, it will either disregard or process the packet. The network device of a firewall only disregards packets which are invalid in some network-technical way. We won’t get into the details of which packets are disregarded automatically, but consider these disregarded packets malformed in some way. The most important thing is: The rest is being processed!! Here’s where firewalls really kick in.
Iptables is such a firewall, and a very powerfull one! It handles packets based on the type of packet activity, and enqueues the packet in one of its builtin ‘tables’. There are three tables in total.
The first is the mangle table which is responsible for the alteration of service bits in the TCP header. This is hardly used in basic setups (at home or in SOHO).
The second table is the filter queue which is responsible for packet filtering. It has three built-in chains in which you can place your firewall policy rules. Continue reading
This article covers network configuration on Linux, with specific reference to the information needed for the RHCSA EX200 and RHCE EX300 certification exams.
Remember, the exams are hands-on, so Continue reading
cp /etc/sysconfig/network-scripts/ifcfg-eth0 Continue reading
DEVICE=eth0 BOOTPROTO=static HWADDR=00:04:75:D4:C8:F9 IPADDR_START=192.168.0.6 IPADDR_END=192.168.0.10 CLONENUM_START=1 NETMASK=255.255.255.0 ONBOOT=yes TYPE=Ethernet
# Controls IP packet forwarding net.ipv4.ip_forward = 1