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S purchase fioricet online tting up IP Aliasing on A Linux Machine Mini-HOWTOHarish Pillay h.pillay@ieee.org Joy Yokley - Converted document from HTML to DocBook v4.1 (SGML)2001-01-23 purchase fioricet online evision History Revision 1.2 2001-01-26 Revised by: JEY Rev purchase fioricet online sion 1.1 2001-01-24 Revised by: JEY Revision 1.0 1997-01-13 Revised by: HP This i purchase fioricet online a cookbook recipe on how to set up and run IP aliasing on a Linux boxand how to set up the machine to receive e-mail on the aliased IP addresses.---------- purchase fioricet online ------------------------------------------------------------------Table of Contents1. My Setup2. Commands3. Troubleshooting: Questions and Answers 3.1. Q purchase fioricet online estion: How can I keep the settings through a reboot? 3.2. Question: How do I set up the IP aliased machine to receive e-mail on the various alias purchase fioricet online d IP addresses (on a machine using sendmail)? 4. Acknowledgements-----------------------------------------------------------------------------1. My Set purchase fioricet online p * IP Alias is standard in kernels 2.0.x and 2.2.x, and available as a compile-time option in 2.4.x (IP Alias has been deprecated in 2.4.x and repla purchase fioricet online ed by a more powerful firewalling mechanism.) * IP Alias compiled as a loadable module. You would have indicated in the "make config" command to make purchase fioricet online your kernel, that you want the IP Masq to be compiled as a (M)odule. Check the Modules HOW-TO (if that exists) or check the info in /usr/src/linux/Doc purchase fioricet online mentation/modules.txt. * I have to support 2 additional IPs over and above the IP already allocated to me. * A D-Link DE620 pocket adapter (not i purchase fioricet online portant, works with any Linux supported network adapter). -----------------------------------------------------------------------------2. Commands 1. L purchase fioricet online ad the IP Alias module (you can skip this step if you compiled the module into the kernel): /sbin/insmod /lib/modules/`uname -r`/ipv4/ip_alias.o purchase fioricet online 2. Setup the loopback, eth0, and all the IP addresses beginning with the main IP address for the eth0 interface: /sbin/ifconfig lo 127.0.0.1 purchase fioricet online /sbin/ifconfig eth0 up /sbin/ifconfig eth0 172.16.3.1 purchase fioricet online /sbin/ifconfig eth0:0 172.16.3.10 /sbin/ifconfig eth0:1 172.16.3.100 purchase fioricet online 172.16.3.1 is the main IP address, while .10 and .100 are the aliases. The magic is the eth0:x where x=0,1,2,...n for the different IP addresses purchase fioricet online The main IP address does not need to be aliased. 3. Setup the routes. First route the loopback, then the net, and finally, the various IP addresses s purchase fioricet online arting with the default (originally allocated) one: /sbin/route add -net 127.0.0.0 /sbin/route add -net 172.16.3 purchase fioricet online 0 dev eth0 /sbin/route add -host 172.16.3.1 dev eth0 /sbin/route add -host 172.16.3.10 dev eth0:0 purchase fioricet online /sbin/route add -host 172.16.3.100 dev eth0:1 /sbin/route add default gw 172.16.3.200 purchase fioricet online That's it. In the example IP address above, I am using the Private IP addresses (RFC1918) for illustrative purposes. Substitute them with your own off purchase fioricet online cial orprivate IP addresses.The example shows only 3 IP addresses. The max is defined to be 256 in /usr/include/linux/net_alias.h. 256 IP addresses on ONE c purchase fioricet online rd is a lot :-)!Here's what my /sbin/ifconfig looks like:lo Link encap:Local Loopback i purchase fioricet online et addr:127.0.0.1 Bcast:127.255.255.255 Mask:255.0.0.0 UP BROADCAST LOOPBACK RUNNING MTU:3584 Metric:1 purchase fioricet online RX packets:5088 errors:0 dropped:0 overruns:0 TX packets:5088 errors:0 dropped:0 overruns:0 purchase fioricet online eth0 Link encap:10Mbps Ethernet HWaddr 00:8E:B8:83:19:20 purchase fioricet online inet addr:172.16.3.1 Bcast:172.16.3.255 Mask:255.255.255.0 UP BROADCAST RUNNING PROMISC MULTICAST MTU purchase fioricet online 1500 Metric:1 RX packets:334036 errors:0 dropped:0 overruns:0 TX packets:11605 errors:0 dropped: purchase fioricet online overruns:0 Interrupt:7 Base address:0x378 purchase fioricet online eth0:0 Link encap:10Mbps Ethernet HWaddr 00:8E:B8:83:19:20 inet addr:172.16 purchase fioricet online 3.10 Bcast:172.16.3.255 Mask:255.255.255.0 UP BROADCAST RUNNING MTU:1500 Metric:1 RX pack purchase fioricet online ts:0 errors:0 dropped:0 overruns:0 TX packets:0 errors:0 dropped:0 overruns:0 purchase fioricet online eth0:1 Link encap:10Mbps Ethernet HWaddr 00:8E:B8:83:19:20 purchase fioricet online inet addr:172.16.3.100 Bcast:172.16.3.255 Mask:255.255.255.0 UP BROADCAST RUNNING MTU:1500 Metric:1 purchase fioricet online RX packets:1 errors:0 dropped:0 overruns:0 TX packets:0 errors:0 dropped:0 overruns:0 purchase fioricet online And /proc/net/aliases:device family address eth0:0 2 172.16.3.10 purchase fioricet online eth0:1 2 172.16.3.100 And /proc/net/alias_types:type name n_ purchase fioricet online ttach 2 ip 2 Of course, the stuff in /proc purchase fioricet online net was created by the ifconfig command and notby hand!-----------------------------------------------------------------------------3. Troubleshooting: Ques purchase fioricet online ions and Answers3.1. Question: How can I keep the settings through a reboot?Answer: Whether you are using BSD-style or SysV-style (Redhat?? for example) ini purchase fioricet online , you can always include it in /etc/rc.d/rc.local. Here's what I have onmy SysV init system (Redhat?? 3.0.3 and 4.0):My /etc/rc.d/rc.local: (edited to show purchase fioricet online he relevant portions)#setting up IP alias interfaces echo "Setting 172.16.3.1, 172.16.3.10, 172.16.3.100 IP Ali purchase fioricet online ses ..." /sbin/ifconfig lo 127.0.0.1 /sbin/ifconfig eth0 up purchase fioricet online /sbin/ifconfig eth0 172.16.3.1 /sbin/ifconfig eth0:0 172.16.3.10 purchase fioricet online /sbin/ifconfig eth0:1 172.16.3.100 #setting up the routes purchase fioricet online echo "Setting IP routes ..." /sbin/route add -net 127.0.0.0 purchase fioricet online /sbin/route add -net 172.16.3.0 dev eth0 /sbin/route add -host 172.16.3.1 eth0 purchase fioricet online /sbin/route add -host 172.16.3.10 eth0:0 /sbin/route add -host 172.16.3.100 eth0:1 purchase fioricet online /sbin/route add default gw 172.16.3.200 # -----------------------------------------------------------------------------3.2. Question: How do I set up the IP aliased machine to receive e-mail onthe various aliased IP addresses (on a machine using sendmail)?Answer: Create (if it doesn't already exist) a file called, /etc/mynames.cw,for example. The file does not have to be this exact name nor inthe /etc directory.In that file, place the official domain names of the aliased IP addresses. Ifthese aliased IP addresses do not have a domain name, then you can place theIP address itself.The /etc/mynames.cw might look like this:# /etc/mynames.cw - include all aliases for your machine here; # is a comment domain.one.net domain.two.com domain.three.org 4.5.6.7 In your sendmail.cf file, where it defines a file class macro Fw, add thefollowing: ################## # local info #
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