Hosts file is being cached - comm channel is using an old version

[Former Member]

We are on XI 7.0.

I wonder if anybody has encountered this problem before. We are using the file adapter to send a file to another server and the server has been moved and now has a new IP address.

We just changed the IP address in the hosts file and the communication channel is still trying to send the data to the old IP address. No changes have been made to the comm channel (so this is definitely not a cpa cache issue!).

The (unix aix) OS recognises that the host has been changed - if we ping the hostname from the OS it resolves to the new IP address.

I have seen this once before and the only way we were able to resolve it was by re-starting the java stack.

Please let me know whether there is another way we can resolve this issue.

Thanks

Richard

[santhosh_kumarv · Accepted solution]

I had a similar issue and only restart of Java stack helped to resolve it....

You could also try start/stop the Communication Channel.... not sure if this can help...

~Sanv...

[Former Member]

Here is what SAP said:

The mapping between physical hostname and IP address might be cached

in the JVM itself using class "InetAddress".

Besides the jdk 1.4 documentation for InetAddress has relevant

information to share, maybe you wish to review the same.

Please refer the info via:

http://java.sun.com/j2se/1.4.2/docs/api/java/net/InetAddress.html

To help resolve clearing the Java Cache you need to reset the JDK

property "sun.net.inetaddr.ttl".

Detailed information can be sourced via access of link:

http://www.rgagnon.com/javadetails/java-0445.html

To overcome such kind of issue, SAP has High Availability for its

landscape. For instance, two machines share the same Virtual Hostname.

Under this situation, the switchover can be done smoothly. And JVM

does not need to be restarted.

This works fine - we set the time out to 2 days so that the cache refreshes itself periodically.

[Former Member]

Thanks Chris. Restarting the java stack fixes the problem, but I need to find a proper fix for this.

I raised a message with sap in parallel and they have come back with suggestions. I'll update everyone once we've tested this out.

[Former Member]

Yes using the Ip address in the CC will definitely work.

I want to resolve the issue of the hosts file being cahced though.

How is it possible to resolve the issue of the hosts file being cached?

We have FTPS connections where the CN name in the cert has to equal the hostname. They do not work if the hostname resolves to the old Ip address.

[Former Member]

Richard,

Does this happen even after a full restart (dunno whether this happens in production, in this case a full restart is not always acceptable ) ... Maybe the FCC uses the WAS hosts cache (I doubt this, but worth giving a try), so maybe you could reset this cache from SMICM tcode (you may have to do it for each AS) ?

Rgds

Chris

[Former Member]

Abishek - please read the post again.

The CC referes to the hostname. We changed the Ip address of the hostname in the hosts file - hence the new Ip address should be resolved correctly from the hosts file. Understand?

SXI_CACHE makes no diffenece.

[former_member200962]

Understand?

Understood.

Now can you use the IP address instead of the hostname in the CC and then check? Now this is a workaround, when your CC does not point to the server using its name you can use the IP address instead......I suppose you are using NFS....in the target directory section of the CC replace servername by IP address

Regards,

Abhishek.

[Former Member]

did u try the IP address drectly instead of the hostname

[prasannakrishna_mynam]

Hi Richard,

It might be the reason that the cache is not refreshed, try with SXI_CACHE cache and perform full cache. It might resolve your issue.

Regards,

Prasanna

[former_member200962]

We are using the file adapter to send a file to another server and the server has been moved and now has a new IP 
address. 
No changes have been made to the comm channel (so this is definitely not a cpa cache issue!).

IP address changed......however no changes made to the CC....so how is the CC going to know that the file needs to be send to a new server and not to the older server

Since no change has been made to ID (i.e. CC) refreshing CPA cache or restarting the java stack will make no difference.

So make the change to the Channel and then test your scenario.....if you do not change the channel settings then may be there is no other way to sort out the issue.

Regards,

Abhishek.

[Former Member]

No that doesn't work. Even if I create a new channel and use the hostname it still sends to the old Ip address.

This is definitely not a cpa cache issue as these replies indicate.

It is as if XI is caching the contents of the hosts file.

[Former Member]

Hello ,

1) Think this issue occured ,as you didnt turn off the channel ,while doing the changes .Anyways Restart the node.This is only one option .or start the adapter on which CC is running.

[Former Member]

That didn't help. Has anyone else seen this problem?