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How to…Configure SAP Webdispatcher as a reverse proxy

January 10, 2006 | 1,691 Views |
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This how to guide describes configuring SAP Web Dispatcher as a reverse proxy for the SAP Enterprise Portal so that you can easily publish the SAP Portal over the Internet.
Step: 1
Copy the following 2 files to a directory on the host where you want to configure the Web dispatcher:
• sapwebdisp.exe • icmadmin.SAR
from the following location of the Portal Server:
drive:\usr\sap\SID\JCxx\exe The Uncar the file icmadmin.SAR, using SAPCAR tool. Step: 2 In the Command prompt go to the directory where you have copied the above 2 files and enter,
sapwebdisp -bootstrap
This will generate the profile file (sapwebdisp.pfl) for the first time usage.
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Step: 3
After the PFL file is generated successfully as shown above, the URL to call:
http://HOST-FOR-WEBDISP:PORT/sap/wdisp/admin/default.html
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User: icmadm
Password: XXXXXXX
The user name and password is generated during the configuration of the Webdispatcher for the first time.
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Step: 4
You can access your portal now via following URL:
http://HOST-FOR-WEBDISP:PORT/irj
Step: 5
If you need to run your Webdispatcher again then use the following command from command prompt.
sapwebdisp pf=sapwebdisp.pfl
Check the process running in the Task manager:
image
Step: 6
You can also install the webdispatcher to run as a NT service. You need to first download ntscmgr.exe from Service Market Place and then use the following command to install the web dispatcher.
NOTE:
Check for the ntscmgr.exe file in the folder drive\usr\sap\SID\JCxx\exe\ folder before trying to download from the Service Market Place.
ntscmgr install SAPWebdispatcher -b drive:\usr\sap\SID\ JCxx\exe\sapwebdisp.exe -p service pf=sapwebdisp.pfl
Step: 7
If the above command somehow didn’t work properly, to fix this you need to do the following:
1. Edit the registry entry by running the program regedit. 2. Do a search for “SAPWebdispatcher” and change the ImagePath to where your sapwebdisp.exe is currently residing.
drive:\usr\sap\SID\JCxx\exe\sapwebdisp.exe service pf=sapwebdisp.pfl
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Step: 8
The URL redirect:
If you want to access the portal using the URL http:// HOST-FOR-WEBDISP:PORT and you are using SAP Webdispatcher, then you need to redirect the above URL to http:// HOST-FOR-WEBDISP:PORT/irj/index.html. This can be achieved by editing the sapwebdisp.pfl file and adding the following parameter,
# SAP Web Dispatcher Web Administration
icm/HTTP/redirect_0 = PREFIX=/, TO=/irj/index.html
After doing this, restart the SAP Webdispatcher.
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19 Comments

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  1. Former Member
    Hello Debasis,

    the content of your blog is somehow similarly as in the documentation and the webdisp notes but much easier to read and to follow.

    Well done.

    Juergen

    (0) 
  2. Former Member
    Hi Debasis,

    Thanks for your contribution! However, when I’m trying to set up the Webdispatcher based on the steps provided in your weblog it seems some dll’s are missing. I’m installing WebDisp on a seperate box (W2000)without any SAP software. When you start with sapwebdisp -bootstrap it returns the following message:

    The following files must be in the path described by
    the environment variable “PATH”:
    icuuc26.dll, icudt26l.dll, icuin26.dll [nlsui0.c 1458] pid = 1932

    Are you sure step 1 doesn’t contain any other activities?

    Cheers!

    Frodo

    (0) 
    1. Hi Frodo

      Yes, you are right. I have also came across the same situation what you are facing now. The missing DLLs. But if you can check your Portal server (drive:\WINNT\System32) you have all the above DLLs in this folder. Please copy these missing DLLs to the Web Dispatcher host. It will solve the issue.

      Regards,
      Debasis

      (0) 
      1. Former Member
        Debasis
        I have installed the web dispatcher as per your blog.  I had issues with port numbers first so I changed the sapwebdisp.pfl file and restarted the sapwebdispter.  I am now getting the errors for the missing DLL’s and cannot start the webdispatcher.
        I can not copy these from my portal servers as my portal is running on UNIX.

        Can you suggest anything?

        (0) 
  3. Former Member
    Am I correct in saying that this does not really replace the IISProxy?
    Can you configure single-sign on with Windows Authentication in any way using the webdispatcher?
    (0) 
    1. Yes, at the moment the SAP Web Dispatcher is configured as a LB rather than a full fledged Reverse Proxy. For a full fledged reverse proxy, you can use any of the 3rd party reverse proxy or SPNego with SAP Webdispatcher can be used. Please refer to the SAP notes: 886214 – End of Maintenance of IisProxy module – Jan, 2006 for more details.

      Regards,
      Debasis

      (0) 
  4. Deidre Logan
    hello there,

    We are trying to get messages our of SAP XI which is inside our firewall and send a message via the AS2 adapter (HTTP/HTTPS)through the internal firewall through the DMZ (how to get it through the DMZ) to our outside partner.  Now I thought I needed a Reverse Proxy to do this and I already have the SAp web dispatcher up and running on a server in the DMZ. 

    I thought that the SAP Web Dispatcher is only for HTTP/HTTPS traffic from the outside into your company?  Are you using the reverse proxy for outbound messages?

    Thanks in assisting my learning.

    Deidre Logan

    (0) 
    1. Hi,

      At the moment, I have configured the SAP Webdispatcher as a LB, since I am using the message servere port and host name to configure that. But for a full fledged reverse proxy you need to use SAP Webdispatcher with SPNego or any 3rd party reverse proxy server. Please refer SAP notes 886214 – End of Maintenance of IisProxy module – Jan, 2006.

      (0) 
  5. Serge Muts
    Hi Debasis,
    what I see from the steps in the blog you set up the SAP Web Dispatcher as a load balancer not as a reverse proxy. The SAP Web Dispatcher can forward the requests and load balance, however the responses bypass the SAP Web Dispatcher entirely. The Web Dispatcher is not meant to be a full reverse proxy. I think this is an important distinction.

    In the help (http://help.sap.com/saphelp_nw04/helpdata/en/e9/3bb7f8f6ea4e938ef0b9687cbb6c14/frameset.htm) under section “structure of the web dispatcher” it reads:
    “The response from the application server does not pass via the Web dispatcher again to the client – it goes direct to the client (via a proxy, if the network is configured with one).”

    Therefore it cannot be used as a full reverse proxy.

    Regards,
    Serge

    (0) 
    2. I have no idea whether the SAP Webdispatcher can be configured for URL rewriting, but in my case I am doing a URL redirect using the *redirect* parameters. Since IISProxy is able to do a URL rewriting and redirect, so there are limitations with SAP Web dispatcher.

      If you look into the SAP help for the SPNego module (introduced from SP15), you can achieve the NTLM functionality using SAP Webdispatcher.

      SPNego:
      http://help.sap.com/saphelp_nw04/helpdata/en/43/4bd58c6c5e5f34e10000000a1553f6/frameset.htm

      (0) 
  6. Former Member
    Is possible to redirect HTTP to HTTPS ??

    I use your steps to use Webdispatcher as reverse proxy and redirect in HTTP and works fine. I Configure EP to support HTTP and HTTPS
    http://portal.mydomain.com:50000/irj/portal
    https://portal.mydomain.com:50001/irj/portal
    # Profile generated by sapwebdisp bootstrap
    # unique instance number
    SAPSYSTEM = 0
    # add default directory settings
    DIR_EXECUTABLE = .
    DIR_INSTANCE = .
    # Accessibility of Message Servers
    rdisp/mshost = portal.mydomain.com
    ms/http_port = 8101
    # SAP Web Dispatcher Parameter
    wdisp/auto_refresh = 120
    wdisp/max_servers = 100
    #wdisp/ssl_encrypt = 2
    wdisp/shm_attach_mode = 6
    # configuration for large scenario
    icm/max_conn      = 16384
    icm/max_sockets   = 16384
    icm/req_queue_len = 6000
    icm/min_threads   = 100
    icm/max_threads   = 250
    mpi/total_size_MB = 500
    mpi/max_pipes     = 21000
    #maximum number of concurrent connections to one server
    wdisp/HTTP/max_pooled_con = 2000
    wdisp/HTTPS/max_pooled_con = 2000
    # SAP Web Dispatcher Ports
    icm/server_port_0 = PROT=HTTP,PORT=80
    # SAP Web Dispatcher Web Administration
    icm/HTTP/admin_0 = PREFIX=/sap/wdisp/admin,DOCROOT=./admin,AUTHFILE=icmauth.txt
    icm/HTTP/redirect_0 = PREFIX=/, TO=/irj/portal/index.html

    (0) 

    1. Try using icm/HTTP/redirect_XX for redirecting the request between protocols. Debasis

      (0) 
  7. Former Member
    Hi Debasis,

    Thanks for this web log. I was able to install web dispatcher on my laptop using the NetWeaver Sneak preview. Question for you, how should we change the profile file to include additional j2ee instances against which you want to load balance.

    (0) 
  8. Former Member

    I’ve installed SAPWebDispatcher (note 834184), for EP 7 in a MSCS, right after this i tried to move group between the nodes and i noticed that the SCS instance has been damaged. (cannot start it manually – error 1053:the service didn’t respond to the start or control request in a timely fashion)<br/><br/>I’m not sure for some parameters in the wd.pfl profile, in the note it’s mentioned:<br/>SAPSYSTEMNAME=JEE<br/>INSTANCE_NAME=WD05<br/>SAPSYSTEM=06<br/>–

    <br/>What should be the right values?<br/>SAPSYSTEMNAME should be the <SID> ?<br/>INSTANCE_NAME should be like above? or the name of one of the nodes ?<br/>—

    <br/>Please advice, thank you , Avi

    (0) 
  11. Former Member

    Hi …

    Nice Blog, a bit more information regarding configuration of response headers and other stuff on web dispatcher would be a great add on. …

    could you suggest how to make changes to response headers in Web Dispatcher? I am trying to access a GW box in this kind of a scenario –

    UI5App deployed on GW Box1 <— > SAP WebDispatcher <—> GW Box2

    I am getting Access-Control-Allow-Origin Error.

    Thanks.

    (0) 

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