1. CIS 193A – Lesson9 Network Infrastructure

2. CIS 193A – Lesson9 Focus Question What are three high level subnets a corporate intranet will want to support?

3. CIS 193A – Lesson9 A Simple Topology

4. CIS 193A – Lesson9 Computer Identity Hostname –/etc/hosts # IP address and FQDN –/etc/sysconfig/network # FQDN Static IP information –/etc/sysconfig/network # default gw –/etc/sysconfig/network-scripts/ifcfg-eth* –/etc/resolv.conf # domain nameserver

5. CIS 193A – Lesson9 Content of ifcfg-eth0 DEVICE=eth0 ONBOOT=yes BOOTPROTO=static IPADDR=207.62.186.9 NETMASK=255.255.255.224 BROADCAST=207.62.186.31

6. CIS 193A – Lesson9 Setting the Default Gateway route add default gw 172.30.1.1 Note that the address must be on a local network interface. GATEWAY=172.30.1.1 This variable may be set either in /etc/sysconfig/network or in the appropriate /etc/sysconfig/network-scripts/ifcfg-eth? file.

7. CIS 193A – Lesson9 Routing For temporary routing: –echo 1 > /proc/sys/net/ipv4/ip_forward –echo a 0 to turn off routing For permanent routing through reboots: –edit /etc/sysctl.conf and set: net.ipv4.ip_forward = 1

8. CIS 193A – Lesson9 Review

9. CIS 193A – Lesson9 Focus Question What are three high level subnets a corporate intranet will want to support? A Corporation may very well want a subnet for a branch office; it may want a public web and/or mail server on a screened subnet (DMZ); it may want a separate subnet for VPN connections from remote users, and it may want its primary intranet subnetted for different departments e.g. executive, development, support, sales, testing …