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General Questions about Spinneret — Parallax Forums

General Questions about Spinneret

sylvie369sylvie369 Posts: 1,622
edited 2011-10-13 14:53 in Accessories
I am largely networking-ignorant and I'm wondering about what the Spinneret is for. I have what I think is a fairly standard home network and internet connection, with a cable modem and a Linksys wireless router. I wonder if I'm thinking reasonably about what I could do if I had a Spinneret.

- It's a webserver, apparently. Does that mean I could set it up with files on an SD card that are accessible from any computer on the internet? That's my understanding of "webserver". I wonder how it applies, though, with my kind of network connection. Would other computers be able to "see" it and access its files? Could I set it up to do that without completely compromising my home network security?

- It has I/O ports. Could those be read/controlled from a computer elsewhere on the network? For example, could I connect a port to a temperature sensor and read my apartment's temperature through a webpage? Could I connect a port to a servo and control it through a webpage using a computer elsewhere (e.g., at my office)? Again, could I do these things without compromising my home network security?

Assuming that it CAN do these things, what kind of software tools do you use to set up the webpages?

I'm tempted to get a Spinneret and try to do some of these things, but I'm so network ignorant that I feel like I'm trying to read Romanian when I look at people's descriptions of their projects.

Comments

  • TorTor Posts: 2,010
    edited 2011-10-13 07:14
    sylvie369 wrote: »
    - It's a webserver, apparently. Does that mean I could set it up with files on an SD card that are accessible from any computer on the internet? That's my understanding of "webserver". I wonder how it applies, though, with my kind of network connection. Would other computers be able to "see" it and access its files? Could I set it up to do that without completely compromising my home network security?
    Your Linksys wireless router probably has some Ethernet (RJ45) ports too, if so then there's often 4 of them (in addition there's a 'wan' RJ45 port that connects to your cable modem). If it doesn't have ethernet ports and only wireless then you would need a wireless adapter for your Spinneret and it would get slightly complicated. If you do have an available Ethernet port then it's reasonably simple to get a secure setup:
    1: Give the Spinneret a fixed IP address (not DHCP). (NB: I'm not familiar with how the Spinneret handles this though - these are generic instructions for how to securely connect a web server on your internal home network to the Internet)
    2: Set up port forwarding in your Linksys router: The router should have a configuration option where you can forward port 80 (as seen externally) to port 80 on the internal IP address you gave your Spinneret. (The internal IP address will typically be something starting with 192.168, or, sometimes, 10., by the way. These are never visible externally. But the Linksys router takes care of that, via NAT (Network Address Translation).
    3: Some cable providers will give you more than one 'external' IP address, others will give you only one. If there's only one then your webserver's IP address will be the IP address of your Linksys router (as seen from the Internet), but in this case you don't have to worry about that (i.e. ignore step 3). If you have several IP addresses to select from then you can map one of those external IP addresses to the internal (NAT) IP address you gave your Spinneret. So, this step 3 applies only if you can select from a number of external IP addresses - it gives you one more configuration option.

    As for your other questions, w.r.t. to network security it is all in what's described above: Map the HTTP port (port 80) to a specific port (port 80, again) onto the IP address you gave your Spinneret. If that is a fixed address (so that you don't get a different one every time you power on your local computers and Spinneret) then you have established a mapping that will not affect anything else on your network.

    -Tor
  • sylvie369sylvie369 Posts: 1,622
    edited 2011-10-13 07:40
    I do have available Ethernet ports, and yes, I'd expect to use one to connect the Spinneret.

    My internet provider says
    Road Runner® uses Dynamic Host Configuration Protocol (DHCP) to assign IP addresses dynamically. This means that you will not always have the same IP address.

    I notice that Jago (mike) in this thread is having issues with that:

    http://forums.parallax.com/showthread.php?134966-Spinneret-and-SHT11

    and from my limited understanding, that not having a static IP would be a problem when trying to access the Spinneret from outside. Is there a solution to that? Or does having a dynamically-allocated IP address limit me to only being able to communicate with the Spinneret from within my home network? (and yes, as far as I can see, there's no way to get a static IP with my provider).

    Edit: Okay, I found Jeff's (OBC's) document about making the Spinneret accessible to the internet. It's very clear - except that if I'm understanding things, it also assumes a static IP for my router. It explains ports and port forwarding very clearly, though.
  • TorTor Posts: 2,010
    edited 2011-10-13 13:02
    sylvie369 wrote: »
    and from my limited understanding, that not having a static IP would be a problem when trying to access the Spinneret from outside. Is there a solution to that?
    The solution to that can be so-called dynamic DNS, where you acquire a domain name and you update the IP address for your server, registered on that domain, whenever it changes. Search for 'dynamic dns' in the famous web search engine, and one of the early entries is one for free dynamic dns.

    The way it works is that your webserver gets a name such as www.domain.name, where this external DNS server (managed by the dynamic dns provider) translates it to an IP address. Your system will then have to connect to their services and update that IP address whenever it changes, which is often connected to restarts of your modem connection. But not always, as your home network gets its (external) IP by DHCP from your cable ISP it's possible to set a 'lease time' limit so that your router would automatically ask for and get an updated (changed) IP after some hours, days or weeks of uptime. At other times you'll get the same IP as you had before even after a power down/power up of your connection.

    -Tor
  • sylvie369sylvie369 Posts: 1,622
    edited 2011-10-13 14:53
    Ah, I see. This is EXTREMELY helpful. I think I understand a lot more now. I'll give it a shot - this is enough to make me think that getting a Spinneret would be worthwhile.

    Thanks !
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