Alter synchronization subscription

[eric_verhorstert]

To change the subscription at the client site we use the script:

alter synchronization subscription mydownload type tcpip address 'host=myhost;port=2439;' "

This forces the client to use port 2439. Reading some documentation, it seems not necessary to set port 2439 at the client site.

We hope that when we remove the port the software will choose a port that is available.

If we run the script "alter synchronization subscription mydownload type tcpip address 'host=myhost;' " will that remove the port?

Thanks

Eric

[jeff_albion]

Hi Eric,

Yes, your SQL provided will remove the 'port' information in the synchronziation subscription. You can check the current settings in the remote by issuing:

    SELECT * FROM SYS.SYSSYNCSUBSCRIPTIONS;

Reading some documentation, it seems not necessary to set port 2439 at the client site. 

If you do not set the PORT value, you will get the 'default' value, depending on the protocol you are using. For TCPIP, this is still '2439': http://dcx.sybase.com/index.html#sa160/en/mlclient/mc-conparm-s-5802886.html

We hope that when we remove the port the software will choose a port that is available.

If you do not supply the PORT, we will assume you are requesting the 'default' port (as specified at the documentation link). There is no mechanism for MobiLink clients to 'auto-pick' open ports on a server - they must be specified at the client, via the synchronziation subscription/profile options.

If you need to set up mulitple MobiLink server ports (e.g. for testing/UA/etc.), it is recommended to use different synchronization profiles for this situation: http://dcx.sybase.com/index.html#sa160/en/mlclient/mc-syncprofile.html

Regards,

Jeff Albion

SAP Active Global Support

[eric_verhorstert]

Thanks for the answer. I probably do not understand the way the communication is set up between the Mobilink Client and the Mobilink Server. Mobilink server uses port 2439. Now we have a client that can not connect to the Mobilink server, possible due to firewall settings.

So, I thought we have to open port 2439 on the client to solve the communication problem. Reading you answer over and over again and reading the help again it seems that the port we set at the client site is the port on which the Mobilink server is set up to listen on.

How can we proceed to find out why this firewall (setup and managed by IBM) is blocking Mobilink client? Is there a port that should be opened on the client site? Should we ask them to trust SQL Anywhere within the firewall?

Btw we run the sql command "SYNCHRONIZE PROFILE mydownload TIMEOUT 800" to download the data.

Thanks

Eric

[jeff_albion]

Now we have a client that can not connect to the Mobilink server, possible due to firewall settings.

Is it just the one client, or can no clients connect to this server?

Btw we run the sql command "SYNCHRONIZE PROFILE mydownload TIMEOUT 800" to download the data.

You can check the current synchronization profile settings (which can override the synchronization subscription settings), using the statement:

SELECT * FROM SYS.SYSSYNCPROFILE WHERE profile_name = 'mydownload';

How can we proceed to find out why this firewall (setup and managed by IBM) is blocking Mobilink client? Is there a port that should be opened on the client site? Should we ask them to trust SQL Anywhere within the firewall?

If you are synchronizing directly using the TCP/IP protocol, yes you will need a direct TCP route open between the MobiLink client and MobiLink server to enable synchronization. I would suggest using network diagnostic tools (such as ping, tracert, Wireshark, and nmap) to confirm that the port is indeed 'open' from the client side and can be directly contacted by the client. If you suspect that there is a firewall blocking TCP access, you will need to consult your network administrator to see if this access can be granted in your environment.

---

Many customers cannot use direct TCP for security reasons through a firewall. However, often in these cases, many customers will still allow in-bound HTTP connections to support a corporate website in a DMZ. For these situations, MobiLink clients can 'piggy-back' on the open webserver port by using HTTP to perform synchronizations and use the Relay Server from MobiLink's 'Outbound Enabler' to get through any internal firewalls, going through forward or reverse HTTP proxies, as required.

See: http://dcx.sybase.com/index.html#sa160/en/relayserver/ml-relayserver-s-5824070.html

Regards,

Jeff Albion

SAP Active Global Support

[eric_verhorstert]

Thanks,

All clients can connect to the Mobilink Server except this one.

Conclusion:

If we open port 2439 in the firewall on the client site the problem is solved?

If there is a other port open on the client site we have to use option "clientport"?

I would appreciate to hear if the conclusion is correct so we can send this to the people responsible for the firewall.

Thanks

Eric

[jeff_albion]

If we open port 2439 in the firewall on the client site the problem is solved?

When you say "client site", are you really referring to the side where the MobiLink server is located? (as in, this is located at your customer or client site?)

Outbound TCP connections typically use the ephemeral ports (49152 to 65535), so I'm not sure how your network is configured in this particular instance if you're referring to an outbound port from a MobiLink client.

If you're referring to an inbound TCP MobiLink server port, yes this is correct.

If there is a other port open on the client site we have to use option "clientport"?

If there is a different non-standard (other than 2439) TCP port opened to get to the MobiLink server, yes, your clients will need to use the 'PORT' network synchronization parameter to contact the MobiLink server (not 'ClientPort' - that is the ephmeral outbound port for the local computer where the MobiLink client is located).

Regards,

Jeff Albion

SAP Active Global Support