ip address change and remsh quit working

[mike worrell]

Hi all,
We have a system called fifrux22, it's IP addresse was changed.
I have a script that does a remsh ffpdink bdf and pipes to a file. It quit working after addy change... when i do manually it says remsh login incorrect. I get this no matter which server I try to remsh to from fifrux22
Fifrux22 is in all the .rhosts on other boxes.
All worked fine until we changed the ip address. All other boxes can ping fifrux22 just fine.
Anyone out there have any idea what might be causing this? Is there a buffer or cache some place in need of clearing?

Any help would be greatly appreciated
Mike

[Jeff Schussele]

Hi Shanda,

This is most likely due to name resolution.
Make sure:

A) DNS has been updated with the new info - check resolution both by name & IP
B) Make sure all systems involved have updated /etc/hosts files. For some reason R-commands will always check the file even though the nsswitch.conf file spells out to use DNS before files.

HTH,
Jeff

[mike worrell]

The hosts file has the new addy in it.
I can ping by name and ip.

Anything else you can think of?

[Jeff Schussele]

Yep - make sure ALL systems' hosts file is correct.
Then check the location & perms on the .rhosts files. They must be in the controlling user's $HOME dir, they need proper ownership & they *must* be 600 perms.

And I guess I need to ask....
Has this system been rebooted following the IP change?
If not I believe you'll need to do so because there may be an ARP table somewhere that needs to be refreshed with the new IP/MAC entry.

Rgds,
Jeff

[Bill Hassell]

The existence of names/IPs in /etc/hosts does not guarentee the fixing of the problem. Most likely, you have a default switch policy where DNS is first, hosts last. Start by asking your nameserver if it knows you comuter by it's hostname and returns the correct IP address. Now check that your DNS server knows the IP address and will return the name. The tool is nslookup and for testing, always specify both the name/IP PLUS the DNS server's IP address:

nslookup myhost 12.34.56.78
nslookup 87.65.43.21 12.34.56.78

In both examples, we are asking the DNS server at 12.34.56.78 for address resolution. remsh/rcp/rlogin try to authenticate the host by asking the DNS server. Most likely, your records were not updated in the DNS server. You can fix this by editing /etc/hosts (on both machines) to make sure it has the correct host and IP address, and then edit /etc/nsswitch.conf and change the hosts: line to read this way:

hosts: files [NOTFOUND=continue UNAVAIL=continue] dns [NOTFOUND=return UNAVAIL=continue TRYAGAIN=return]

Now, it should work. You can also put the IP address ans well as the hostname in .rhosts:

fifrux22 user1
87.65.43.21 user1

Then try the remsh. The final fix is to correct the problems in the DNS server.

[mike worrell]

Hi Bill,
what we're doing is changing subnets on all servers from 10.8.188.xx to 10.8.197.xx
The weird thing is the i can't remsh from any box that is on 10.8.197.xx to another on 10.8.197.xx. However i can remsh from 10.8.197.xx to a box still on 10.8.188.xx

my nsswitch file is set like you suggested.
i can do a nslookup on each box from each box and get correct name and addy
put additional addy's in each hosts file
still no luck.

any thing else i can try
thanks,
mike