Gill Instruments Limited
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MetStream 100
Page 55
Issue 2
Doc. No. 1955-PS-001
March 2016
6.5.12
Port Forwarding
If the router/server that the MetStream is linked to is connected to the internet, it will have
a Public IP Address. This is assigned by the Internet Service Provider (ISP) and more
often than not it isn’t fixed. If a fixed IP address is required a fee usually has to be paid to
the ISP.
If this IP address (fixed or not) is known then it is possible to access the MetStream
browser page from outside of the subnet that the MetStream is connected to.
The router/server will have a different sub network set of addresses from its external
address. For example; its subnet may be 192.168.1.XXX (any device connected to the
router like PC’s, tablets & the MetStream would see this subnet) and its external IP (this is
the address that any device on the internet side of the router/server would see when they
try to connect) may be 4.85.161.114 (this address would be assigned by the ISP).
Therefore, to connect to the MetStream from outside the subnet, a port forwarding rule
would need to be setup on the router (the exact method varies from router to router). By
default, the MetStreams web server port is set to 80. If, in this example, it is assumed that
the routers subnet is 192.168.1.XXX and therefore the MetStreams IP is fixed at
192.168.1.99 (details of how to do this can be found in the manual) and the routers
external IP has been fixed at 4.85.161.114, then a rule would need to be setup in the router
that means that typing the address & port 4.85.161.114:80 from outside of the routers
subnet would be directed through to the MetStreams web page.
As port 80 is the port used by any device that serves up a web page, it would be advisable
when attempting to setup a port forwarding rule for the MetStream to change this port to
prevent possible conflict. Details on how to do this can be found in Para 6.5.7.
