Home > IT Answers > AS/400 > Client Access: IP or DNS?
Guy553
380 pts.
 Client Access: IP or DNS?
Client Access, Power6, iseries v5r4
Can I tell by looking on the system if my users are accessing the box via IP or DNS or do I have to vist each PC to check config?

Software/Hardware used:
Power6, V5R4 and V6R1, Various Versions of CA
ASKED: Feb 3, 2012  9:58 AM GMT
UPDATED: March 21, 2012  12:20:12 AM GMT
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TomLiotta
66,925 pts.
 
  Help
 Approved Answer - Chosen by Guy553 (Question Asker)
...no way of telling from the system side...

A server can only tell the difference if the client cooperates. That is, there is nothing in the connection itself that indicates how the IP address was obtained.

The connection is always by IP address. By the time a connection is requested, any work that was done by the client to obtain a resolved address is long since been done.

You could run programming on the server that called back to the client and requested data about how the address was obtained. The client would, of course, need complementary programming that could respond.

Other than something like that, the only way I can think of is like I said before -- enable a second IP address on the server and point DNS at the new address. Clients that continued to connect to the old address are the ones not resolving through DNS. If all clients automatically use the new address, then you don't need to fix any of them.

Tom
ANSWERED:  Mar 21, 2012  0:20 AM (GMT)  by TomLiotta   66,925 pts.
 
Other Answers:
You Describe my issue perfectly in your latest answer, I have a Prod and a HA system and I wish to role swap between the two. The issue I have is that I need to identify those users who have had to change their desk top icons over the years for whatever reason to hard code the IP's.
During the Roleswap part of the changes we make is to make the DNS changes to point the users seamlessly to the other server. Obviously the users with Hardcoded IP's will have issues. I want to identify these users now for two reasons,
1. they need changing, but
2. to understand why they are IP hardcoded, they may have an issue with the DNS resolution which I need to fix before I can role swap.
While you sound like you know what I need to do, I have to apologise as I am not sure I understand the resolution, if indeed this is a resolution for this scenario.
I should also mention that my HA environments are locked down when not being used in Production, we have a separate QINTER for my support team so we take down QINTER itself and also close down things like TCP/IP interfaces etc. We do this to stop our clever "IT" users access the systems and messing up my replicated data sets.
Last Wiki Answer Submitted:  Feb 6, 2012  11:07 AM (GMT)  by  Guy553   380 pts.
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just click communication tap in client access, and click PC box -> click LAN box -> double click the TCP/IP and type your server IP address in ‘Host name or ip address box… click ok and ok button…

it ll connected your server….

Pdsathishkumar
 3,665 pts.
 

Pdsathishkum,

How does your answer tell Guy553 whether his users are accessing his system via IP or DNS ?

Bill Poulin

Wpoulin
 2,470 pts.
 

Can I tell by looking on the system if my users are accessing the box via IP or DNS …

No.

But just to be clear, DNS is a TCP/IP application. If DNS is used, then the PC will connect over TCP/IP. And on your AS/400, it will look exactly the same whether DNS resolution was used or not. Either way, the IP address will be the result.

So, I assume that what you are asking is whether a PC is using a hard-coded IP address or it is using a host name that was resolved to an IP address.

I can think of one way that could help you to find out.

This would seem to come up because of something like a planned change for the IP address of your AS/400. If everyone used DNS resolution, you could mostly just update DNS and the PCs would mostly just adapt automatically. But a PC with a hard-coded address would begin to fail to connect.

In a situation like that, all you should need to do is to enable the new address on your AS/400 while keeping the old address active. Update DNS to point to the new address. PCs using DNS will then start connecting through the new interface.

PCs that continue to connect to the old address will be candidates for the hard-coded address group.

Note that the address might be “hard-coded” in the HOSTS table on some PCs.

Tom

TomLiotta
 66,925 pts.
 

Remember, he doesn’t want to “travel” to each PC if he doesn’t have to.

OldSysAdmin
 925 pts.
 

We use the iTera HA software & do specify the IP address in the CA configuration; the IP is defined on both systems but only active on the ‘primary’ system. DNS comes into play for the web application as we re-direct the external DNS server to point to the appropriate IP address for that application.

Splat
 4,945 pts.
 

Can I take it that there is no way of telling from the system side whether the users are coming in using DNS or Hardcoded IP?

If not then that is the correct answer !

Guy553
 380 pts.

…no way of telling from the system side…

A server can only tell the difference if the client cooperates. That is, there is nothing in the connection itself that indicates how the IP address was obtained.

The connection is always by IP address. By the time a connection is requested, any work that was done by the client to obtain a resolved address is long since been done.

You could run programming on the server that called back to the client and requested data about how the address was obtained. The client would, of course, need complementary programming that could respond.

Other than something like that, the only way I can think of is like I said before — enable a second IP address on the server and point DNS at the new address. Clients that continued to connect to the old address are the ones not resolving through DNS. If all clients automatically use the new address, then you don’t need to fix any of them.

Tom

TomLiotta
 66,925 pts.