Remote IP Address Migration Guide

This guide is for the system administrator that manages linux based server via remote shell such as ssh for system administration and has the task of changing the IP addressing of the remote server to different IP addresses. For example, the hosting provider requires the system administrator to change the server's IP addressing (primary address and two aliases) from one netblock to another. The trick is for the system administrator to accomplish this remotely without being locked out of the server or bringing the server offline and requiring local access.

Step 1: Add the new IP addressing to the machine as aliases on the nic without removing the existing IP addressing. Step 2: Verify a valid route to the Internet via the new IP addressing and the route on the new IP block. Step 3: Verify remote access via new IP address, including required firewall modifications Step 4: Flip the addresses, ie: move new addresses to primary interface address and first aliases Step 5: Update all associated domain name and hosts if applicable Step 6: Update daemon configurations such as Apache Step 7: Remove previous IP addressing

Redhat, Fedora, Trustix

Modify network configuration

/etc/sysconfig/network

Network Interface scripts

/etc/sysconfig/network-scripts/ifcfg-eth0

Aliases

/etc/sysconfig/network-scripts/ifcfg-eth0:1

Commands useful during migration to prevent box lockout

/rc/S08ipchains restart && ipchains -L && sleep 60s && /rc/S08ipchains stop

/sbin/ifdown eth0 && sleep 10s && /sbin/ifup eth0

Troubleshooting:

SIOCSIFBRDADDR: Cannot assign requested address

interface address binding locked

You can force the IP address onto the interface with ifconfig command

ifconfig eth0 192.168.215.90 netmask 255.255.255.248 broadcast 192.168.215.95