SM51 list of SAP instance hows "localhost" instead of the name of the host.

[Former Member]

Hi,

In our landscape we are facing an issues related with hostname. in SM51 transaction where we see the list of application servers,there is entry "localhost" instead of it's value which we see in hosts file (/etc/hosts).I want to add one important thing that SAP is on  virtual machines.From the OS level we can see the hostname and it's showing us the correct name.

Any clue would be appreciated.

Thanks,

Rakesh

[Former Member · Accepted solution]

Hi Rakesh,

Please make an entry for the Virtual host name in "/etc/hosts" file.

There is entry for  Physical Host name.Just Remove the comment for the  Virtual Host name and it will be enabled.

Hope its will resolve your issue.

Regards,

Utkarsh

[Former Member]

Hi Everyone.

Thanks for your support which  led me to find the solution for the issue with Virtual host name .

I just got an opportune restart of the server and just before that I made a change in the /etc/hosts file

There was a missing entry for Virtual host name in this file. Actually the entry was there but it was commented.

I had to un-comment it and to make it effective , server reboot was required.

After server reboot , I can see the Virtual host name in the SM51 txn.

Also in DB12, we can see the archive overview, the size of the archive directory which was giving an error earlier.

However , one thing still needs answering if virtual host entry was missing from the hosts file , how did  the following result:

nslookup <Virtual_host_name>

This command was resolving the host name to the correct IP.

I guess DNS stuff is making it happen. I don;t understand that much but there is an entry in the DN server in  the /etc/resolv.conf  file which is taking care of resolution of the virtual host name.

And now,

niping -v -H <virtual_host_name> is resolving to both  physical hostname and virtual hostname...earlier I used to get an error as I posted the screen shot.

I am encouraged to use SCN more often  with so many positive response from the fellow SCNians.

Thanks again,

Rakesh

[csaba_goetz]

Hello Rakesh,

check the local hostname resolution by

   niping -v -H localhost

   nslookup localhost

localhost must be resolved as 127.0.0.1 and vice versa.

This is correct:

   niping -v -H localhost

   ...

   Lookup of hostname: localhost                                (NiHostToAddr)

       --> IP-Addr.: 127.0.0.1

   Lookup of IP-Addr.: 127.0.0.1                                (NiAddrToHost)

       --> Hostname: localhost

   nslookup localhost
   ...

   Name:   localhost
   Address: 127.0.0.1

This is incorrect:

   niping -v -H localhost

   ...

   Lookup of hostname: localhost                                (NiHostToAddr)

       --> IP-Addr.: <IP address not equal to 127.0.0.1>

   Lookup of IP-Addr.: <IP address not equal to 127.0.0.1>                                (NiAddrToHost)

       --> Hostname: localhost

   nslookup localhost
   ...

   Name:   localhost
   Address: <IP address not equal to 127.0.0.1>

If the result in this system is incorrect, /etc/hosts and DNS entries must be corrected first. Hostname in SM51 will then change (after SAP restart).

Best regards,

Adam

[Former Member]

Hello Reagon,

Thanks for the link .. But I couldn't find my solution...

the post said

"Issue is solved by deleting DNS reverse lookup entry which was uppercase and created new one"....

How do I apply that in my scenario? I have shown earlier my Message server's  /etc/hosts entries...

If you can shed some light on what is required to solve the issue, it would be helpful..

Thanks,

rks

[Reagan]

Hello Rakesh

What I wanted you to check is the suggestions provided in the thread and not just the solution.

It looks like the problem is with the hosts file.

Do you know why the entry for virtual host name is commented ?

http://scn.sap.com/thread/3195577

Regards

RB

[former_member188883]

Hi Rakesh,

Assuming your /etc/hosts file entries are correct,

For unix system you may disable the DNS hostname entries and enable the system to read from /etc/hosts file only.

To do so, rename the file /etc/resolv.config.

Hope this helps.

Regards,

Deepak Kori.

[Reagan]

Hello

Check the suggestions provided here:

http://scn.sap.com/thread/3398718

Regards

RB

[Former Member]

Thanks for the reply.

In our set up we have physical host name and virtual hostname  as well.

physical host name : X

Virtual host name : Y

hostname command at OS level resolves to X where as the profile params liek SAPLOCALHOST and SAPDBHOST resolves to Y.

Even the niping command gives error against the virtual host name.

see attached screen sot for niping result

and in the /etc/hosts file:

Point to note is : Virtual host name entry is commented. I have no idea why is that commented or if that is even required here?

Please suggest.

Thanks,

Rakesh

[sunny_pahuja2]

Hello,

Please make sure that If more than one name is specified for one IP address, than the one that corresponds to the hostname should be first.You can also refer to SAP note 129997.

Thanks

Sunny

[hugo_amo]

Hi Rakesh,

The names in SM51 are coming from hostname resolution. Names must be resolved in the same case within all hosts in the landscape.

You can check with the following commands if the settings are OK for DNS and host files in all application servers :

niping -v -H <ip-address>
niping -v -H <hostname>

After this, try to reset the hostname buffer in the SAP system:

SM51 -> Goto -> Host name buffer -> reset -> entire system

Regards,

Hugo

[Manas_Vincit]

Hi Rakesh ,

Check in /etc/hosts file in message server host , if there is entry of localhost ? also check in  SAP profile if there is entry of localhost .

Thanks

Manas