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S vicodin es tting up IP Aliasing on A Linux Machine Mini-HOWTOHarish Pillay h.pillay@ieee.org Joy Yokley - Converted vicodin es document from HTML to DocBook v4.1 (SGML)2001-01-23Revision History vicodin es Revision 1.2 2001-01-26 Revised by: JEY Revi vicodin es ion 1.1 2001-01-24 Revised by: JEY Revision 1.0 1997-01-1 vicodin es Revised by: HP This is a cookbook recipe on how to set up and run IP aliasi vicodin es g on a Linux boxand how to set up the machine to receive e-mail on the aliased IP addresses.------------ vicodin es ----------------------------------------------------------------Table of Contents1. My Setup2. Commands3 vicodin es Troubleshooting: Questions and Answers 3.1. Question: How can I keep the settings through a reboot? vicodin es 3.2. Question: How do I set up the IP aliased machine to receive e-mail on the various aliased vicodin es P addresses (on a machine using sendmail)? 4. Acknowledgements------------------------------------- vicodin es ---------------------------------------1. My Setup * IP Alias is standard in kernels 2.0.x and 2.2.x, a vicodin es d available as a compile-time option in 2.4.x (IP Alias has been deprecated in 2.4.x and replaced vicodin es y a more powerful firewalling mechanism.) * IP Alias compiled as a loadable module. You would have i vicodin es dicated in the "make config" command to make your kernel, that you want the IP Masq to be compiled vicodin es as a (M)odule. Check the Modules HOW-TO (if that exists) or check the info in /usr/src/linux/Document vicodin es tion/modules.txt. * I have to support 2 additional IPs over and above the IP already allocated to vicodin es me. * A D-Link DE620 pocket adapter (not important, works with any Linux supported network adapte vicodin es ). -----------------------------------------------------------------------------2. Commands 1. Load th vicodin es IP Alias module (you can skip this step if you compiled the module into the kernel): /sbin/insmod vicodin es /lib/modules/`uname -r`/ipv4/ip_alias.o 2. Setup the loopback, eth0, and all the IP addr vicodin es sses beginning with the main IP address for the eth0 interface: /sbin/ifconfig lo 127.0.0.1 vicodin es /sbin/ifconfig eth0 up / vicodin es bin/ifconfig eth0 172.16.3.1 /sbin/ifconfig eth0:0 172.16.3.10 vicodin es /sbin/ifconfig eth0:1 172.16.3.100 1 vicodin es 2.16.3.1 is the main IP address, while .10 and .100 are the aliases. The magic is the eth0:x where x= vicodin es ,1,2,...n for the different IP addresses. The main IP address does not need to be aliased. 3. Setu vicodin es the routes. First route the loopback, then the net, and finally, the various IP addresses starting w vicodin es th the default (originally allocated) one: /sbin/route add -net 127.0.0.0 vicodin es /sbin/route add -net 172.16.3.0 dev eth0 /sbin/route add -host vicodin es 72.16.3.1 dev eth0 /sbin/route add -host 172.16.3.10 dev eth0:0 vicodin es /sbin/route add -host 172.16.3.100 dev eth0:1 /sbin/route add default g vicodin es 172.16.3.200 That's it. In the example IP address above, I am using t vicodin es e Private IP addresses (RFC1918) for illustrative purposes. Substitute them with your own official orpri vicodin es ate IP addresses.The example shows only 3 IP addresses. The max is defined to be 256 in /usr/include/lin vicodin es x/net_alias.h. 256 IP addresses on ONE card is a lot :-)!Here's what my /sbin/ifconfig looks like:lo vicodin es Link encap:Local Loopback inet addr:127 vicodin es 0.0.1 Bcast:127.255.255.255 Mask:255.0.0.0 UP BROADCAST LOOPBACK RUN vicodin es ING MTU:3584 Metric:1 RX packets:5088 errors:0 dropped:0 overruns:0 vicodin es TX packets:5088 errors:0 dropped:0 overruns:0 vicodin es eth0 Link encap:10Mbps Ether vicodin es et HWaddr 00:8E:B8:83:19:20 inet addr:172.16.3.1 Bcast:172.16. vicodin es .255 Mask:255.255.255.0 UP BROADCAST RUNNING PROMISC MULTICAST MTU:1500 Metric: vicodin es RX packets:334036 errors:0 dropped:0 overruns:0 vicodin es TX packets:11605 errors:0 dropped:0 overruns:0 Interrupt:7 Base a vicodin es dress:0x378 vicodin es eth0:0 Link encap:10Mbps Ethernet HWaddr 00:8E:B8:83:19:20 vicodin es inet addr:172.16.3.10 Bcast:172.16.3.255 Mask:255.255.255.0 U vicodin es BROADCAST RUNNING MTU:1500 Metric:1 RX packets:0 errors:0 d vicodin es opped:0 overruns:0 TX packets:0 errors:0 dropped:0 overruns:0 vicodin es eth0:1 Link encap:10Mbps Ethernet HWaddr 00:8E:B8:83:19:20 inet addr:172.16.3.100 Bcast:172.16.3.255 Mask:255.255.255.0 UP BROADCAST RUNNING MTU:1500 Metric:1 RX packets:1 errors:0 dropped:0 overruns:0 TX packets:0 errors:0 dropped:0 overruns:0 And /proc/net/aliases:device family address eth0:0 2 172.16.3.10
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