Changing your IP address

The normal mode for the SNIP Caster is to reuse the last IP address and port number which you selected every time it runs.  This address is then known by your NTRIP Clients, because you used a static IP or because you used a dynamic DNS with port forwarding. [During initial installation SNIP will default to use the local host ID at the first time it is run]   In general this is a set once and forget type of setting.

However, if you are using DHCP in your local network, the available IP can sometime change unexpectedly.  You will likely notice this when SNIP restarts after a power cycle with error messages in the console log like the example below:

ERROR: Server not started! – Attempt was on IP: Port:2101    at Sat May 07 2016, 08:13:16AM (local machine time)
ERROR: Opening server socket failed.
ERROR: Unable to start Caster Service, check your settings.

This event occurred recently to the author when one of our routers went out and, once the network was fixed, the machine found itself on another sub-net with a new IP.

The solution is to simply pick from one of the machine’s existing IP values.  How do you find those?  Simple — just set the log threshold level menu to be “minor”  (so more detailed log entries are then visible) and SNIPs log console will tell you what local IP addresses have been found (as well as what was used the prior time), as shown below:

Listing all the local address(es) for this machine (connect the caster to one of these)
Opening socket using:
ERROR: Server not started! – Attempt was on IP: Port:2101  at Sat May 07 2016, 09:03:16AM (local machine time)
ERROR: Opening server socket failed.
ERROR: Unable to start Caster Service, check your settings.

Pick from one of these, entering the new IP in the Caster and Clients tab, and then press Connect.   SNIP will begin servicing clients on that IP:Port combination, and will remember your selection thereafter. The next time SNIP is restarted the connection will occur automatically (presuming you have selected the Auto Start checkbox) and will produce a console entry similar to the example below.  When done, be sure to set the log threshold level back to your preferred level to avoid unwanted clutter.

Caster: Was Started, – Now Listening on IP:    Port:2101  at Sat May 07 2016, 09:10:44AM (local machine time)

Hint:  If you are not using SNIP in a static IP environment, then it is a best practice to establish a “reserved” IP for the machine running SNIP within the dynamic IP range to avoid this issue.  Most devices offering DHCP services (your modem, router, firewall, etc.) provide a means to do this.


Raw TCP/IP IP Details

When using the Raw TCP/IP stream method to allow an older (pre-NTRIP) GNSS Base Station to send data to SNIP, the “incoming” IP is the same IP at which you are operating SNIP, while the port used for the incoming connection is whatever value you select during the setup.  A remote data sender (pre-NTRIP Base Station) can send to this port from any IP address anywhere on the Internet, unless you provide the specific remote IP you wish to allow to connect, see the Raw TCP/IP tab setting for details.  And for obvious security reasons you should always provide the remote IP value when you are able to to limit abuse.   If you are using various firewalls, NAT, DDNS, or VPM methods in you setup, then the remote IP value would reflect the final IP address that SNIP will see.

Do not have a static IP address?

No problem.  SCSC has created a public caster for use by our SNIP customers who do not have a static IP of their  own.  This allows sharing your local base station data with others, even if your only internet connection is from a local DSL connection.

The service is called RTK2go™ and is described further here.


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