View Full Version : Changing IP numbers
01-01-1995, 02:00 AM
Networkers, When I set up my network and AS/400 I followed the advice of our networking guys. Without fully understanding the implications I followed their advice. Now I can no longer connect to their network because they have added new networks that caused a conflict (I am not sure I believe them because I get an error that access was blocked by Border Manager). I have decided to use a new set of IP numbers and have done some experimenting. I have found that I can bring down my main ethernet interface and still connect to the AS/400 via the console using the loopback address. I am confident that all but my primary IP number will be easy to change. Can I create and start a new interface using the old line description or do I need to create a new line also. How will I delete the old interface. It seems to always start. Will I be able to delete it in restricted mode? Are there any instructions on doing this. I have looked at the TCP/IP reference and didn't see anything like "changing your IP number". I am considering using a very small subnet to minimize potential conflicts. I am currently only using 6 addresses. I am also thinking about using the DNS again. I gave up on that after realizing that when the system was in restricted state I couldn't get to the rest of my network or even print. I think I can live with one host file and a DNS. David Morris
06-19-2000, 01:05 PM
David, I am not a 'networker' but may be able to help. We have two mirrored 400's, when we swap the backup to be primary we change their IP addresses so that all users and applications always find whichever is the primary machine. To do this we endtcp and perform the following steps from the console(twinax attached) and then strtcp. 1. GO CFGTCP and take option 1 to configure the TCP setup. Change the autostart option to *YES for address xxx.xxx.xxx.001 and *NO for address xxx.xxx.xxx.002 on the machine that is going to be the source machine. Set the autostart values just the opposite on the machine that is going to be the target. 2. Take option 10 on the CFGTCP menu to change the host table entries. You must create a new entry and remove the old one. Do not do anything with any entry that has an address of other than xxx.xxx.xxx.001 or xxx.xxx.xxx.002. The new Source machine should have an entry with an address of xxx.xxx.xxx.001 and a name of 'I'. The new Target machine should have an entry with an address of xxx.xxx.xxx.002 and names of 'E' and 'E.WASHCORP.COM'. 3. Take option 12 on the CFGTCP menu to change local domain and host names. On the new source machine change any E's to I's and on the new target machine change any I's to E's I am not positive that this is all required or the best approach but I do know that it works for us. After performing the above, all users and applications are useing a different 400 without realizing it. My guess is that you just need the first step in changing the interface. To stop an interface from starting just set the autostart value to *no. Hope this helps some. Scott Mildenberger
06-19-2000, 01:45 PM
David - We recently moved a system from one building to another (and one subnet to another) and here is what we did (from the console): 1)ENDTCP 2)CFGTCP option 1 - Delete the current IP interface 3)CFGTCP option 2 - Delete the current *DFTROUTE 4)CFGTCP option 10 - Delete the host table entry for THIS machine 5)CFGTCP option 1 - Add new IP interface with new IP address 6)CFGTCP option 2 - Add new *DFTROUTE with new NEXT HOP IP ADDRESS 7)CFGTCP option 10 - Add new host table entry for THIS machine 8) STRTCP Depending on your network, you may be able to change using only #1, #2, #5, and #8 - OR - there may be additional steps besides 1-8. HTH, Steve
06-19-2000, 06:51 PM
David, You should be able to use Network Address Translation (NAT) to present a unique IP address to the outside world, while maintaining the original IP address to your local (to your AS/400) devices. Use Operations Navigator in Client Access Express V4R4 to configure NAT. It's actually very easy to do, and the help text on the tool is pretty useful. Just click on the Network node on the Ops Nav tree, go to IP Security, and then right click on that to select CONFIGURE (I think, I'm doing this by memory at the moment, but if it's not exact, it should be close and you'll figure out which ones to click on) and then just configure NAT. The IBM Information Center also has some good advice on how to do this. Also, Bob Cancilla wrote a great article on how to do it on his web site (www.ignite400.com). Or just wait for an upcoming issue of MC (very soon). We're running a How-To article on NAT also. HTH
06-20-2000, 05:58 AM
Shannon, NAT would be ideal. I thought about that, but when I last looked at using NAT I found that I had to have two adapters in my AS/400. I currently have an 100M ethernet adapter installed. I tried to get another 100M ethernet adapter but I was told I had to get the expansion unit even though I have plenty of open slots. I was told that there is not enough bus bandwidth in my 170 unless I add the expansion unit. I also have several 16M Token ring adapters from another machine that could be installed but I never got a strait answer on whether they would work and I since I wouln't be buying them, IBM was not able to help me. When I looked into NAT, I was considering using it as part of my firewall. Now that inexpensive firewall/router appliances are available it doesn't make as much sense. I only wish I could convince the phone company that (this is Montana) that DSL is actually something they should look into. They have been telling me two months for two years. David Morris
06-20-2000, 07:18 AM
yup. you do need that second card. well shoot. sounds like that won't work for you then without a large expense. Sorry!
06-26-2000, 02:35 PM
Steve & Scott, I used your instructions to swap my IP numbers this weekend and everything went very well. Thanks, David Morris
Powered by vBulletin® Version 4.1.5 Copyright © 2013 vBulletin Solutions, Inc. All rights reserved.