I am developing a custom Alexa Skill and have a requirement where I want Alexa to access REST APIs that are hosted locally on http://localhost:8080? Any idea how to do this?
Thanks!
If you really want to do this, and I’m assuming you are hosting the skill on AWS Lambda, it would involve quite a bit of work.
Your local endpoints need to be accessible from outside of your network, which requires port forwarding in your router to your machine where the endpoints are hosted. This needs to be configured in your router.
An easier way is to deploy your project containing the API to something like Heroku, which can be done easily. They give you a domain and make the endpoints accessible to Lambda. This should be possible within their free tier.
Here' a link to a pretty good article about how IP addresses work.
Allowing a device sitting on your local network (eg. a laptop computer or Raspberry Pi connected to your wifi) to be accessed from outside your local network (eg. from a service running on AWS) will involve mapping 2 separate IP addresses:
The IP address assigned to your router (your public IP)
The private IP addresses assigned by your router to your devices (laptop, iPhone, RPi, etc).
You have a couple options for allowing your router's IP (#1) to be accessible from outside your local network:
a. Pay your internet provider to provide you with a static IP address
b. Use a dynamic DNS service such as DuckDNS or No-IP.
Once you have a fixed public IP that can be used to access your router, you will then need to map a port on your router (#1) to the device IP on your local network (#2). This is usually referred to as "port forwarding". Most routers will support configuring this. In effect, your tell your router "when you get a message to : pass it to my laptop :"
Your local private IP address will typically have an IP value like 192.168.0.23 (where the 23 can be anything from 1 to 254).
An outside IP will start with something other than 192. Refer to the first link above regarding IP ranges.
You can google "port forwarding" and "public IP" for more info on how IP addresses and port forwarding work, but hopefully this will help get you started. It may seem a bit complicated at first, but if I can understand it, then anyone can :-)
Related
I am just experimenting with my phone system and I'm wondering how both endpoints know they are on the same LAN, I have both endpoints breaking out to the cloud phone system with two separate public IP addresses, I've segmented them off from each other with a firewall so they can't see each other however every time I attempt a call between the two end points the call is setup as a peer to peer call and attempts to traverse the local LAN via RTP through the firewall, the firewall blocks the RTP communication and the call has no audio.
I am just wondering how both endpoints are realizing they are behind the same firewall/router since they are both registering with the cloud system from different public IP addresses, I wanted the call to be bridged in the cloud and not traverse the local LAN but somehow both endpoints only attempt the call over the LAN every single time and no idea how they're realising they're on the same LAN.
Anyone else encountered this before?
SIP endpoints don't have to know they are on the same LAN. They just make best use of the IP addresses you provide.
Your INVITE request will provide more insight, but from what you write my guess is that you use public IP addresses for your contact/request URI and local IP addresses in your SDP offer. The local IP addresses are probably routable through the firewall.
With ICE and STUN endpoints may select the best IPs for media traffic - but for that to work the RTP/STUN packets should be able to traverse the firewall in your LAN.
Attempts to communicate directly may mean that LAN uses IPs from public ranges or endpoints a SIP proxy were not smart enough to detect NAT in front of your LAN.
So I am kind of new to networking and I'm just interested in the client/server architecture. Let's say you developed a program and the client version ran on a computer and the server version on the server(obviously). In order for the client to connect to the server, it would have to know the ip address of the server (and the port attached so it can be routed to the correct computer/program). Does that mean that the server's ip address can not change? Would you have to specifically tell your ISP to keep the ip address static? Because if both the client and server ip addresses change, then they would have no way to connect and the program wouldn't work... in other words there has to be one constant. When you sign up for a VPS do they give you a static ip address you can bind to from the client version? Thanks!
In order for the client to connect to the server, it would have to know the ip address of the server (and the port attached so it can be routed to the correct computer/program).
Correct.
Does that mean that the server's ip address can not change?
No. In fact, IPs can change at any time. Most servers that are exposed to the public Internet have a static domain name registered in the Internet's DNS system. A client asks DNS to resolve the desired domain name to its current IP address, and then the client can connect to it. But even in private LANs, most routers act as a local DNS server, allowing machines on the same network to discover each other's IP by machine name.
The OS typically handles DNS for you. A client can simply call gethostbyname() or prefferably getaddrinfo(), and the OS will perform DNS queries as needed on the client's behalf and return back the reported IP(s).
Would you have to specifically tell your ISP to keep the ip address static?
You can, but that usually costs extra. And it is not necessary if your server is registered in DNS. And there are free/cheap DNS systems that work with servers that do not have a static IP.
Because if both the client and server ip addresses change, then they would have no way to connect and the program wouldn't work...
That is where DNS comes into play.
in other words there has to be one constant.
A registered domain name that can be resolved by DNS.
When you sign up for a VPS do they give you a static ip address you can bind to from the client version?
It depends on the VPS service, but a more likely scenario would be you are assigned a static sub-domain within the VPS service's main domain. For example, myserver.thevps.com. Or, if you buy your own domain (which can be done very cheaply from any number of providers), you can usually link it to the DNS server operated by your VPS service.
Sorry if I have this in the wrong community but I'm hoping one of you can help me out anyway.
I have a web hosting account with a UK company who I'm happy with, but I'd like to set up a little hosting account from my laptop, just to see if it's possible and easy enough to do really.
Trouble is I've been doing a lot of research online but coming up empty whenit comes to more of a "complete guide". Do any of you know of a good resource for setting up a home server for publishing "Live" websites with custom TLD domain names? I have a localhost server running and files hosted on there but I'm really looking for help with the IP and DNS parts for the custom domains.
For reference, I have a machine running Win7, Appserv 2.5.10, UK broadband and a .co.uk domain name registered with 123-reg.
Any help would be hugely appreciated.
You'll need to:
Point your domain to your laptop.
If you get static public IP address from your ISP, then you can just point the A record to this IP address.
Where do I set this A record? Almost all domain registrars give you a nameserver for free. You point your domain to their nameservers (generally ns1.somedomain.com and ns2.samedomain.com etc.). In the nameserver config, create a A (stands for authoritative) record and put in your static IP address.
What if my ISP doesn't give me an static IP address? This is where services like dyndns come into picture. They give you an agent that you'll install on your laptop, it detects the change in IP address and automatically updates the Nameservers accordingly. There are some free variants of dyndns as well if you don't want to spend money on this.
But my laptops IP address is something like 192.168.x.x and my site runs on localhost (127.0.0.1)? Your laptop is most likely NATed. Think about your public IP address to be that of your router. You will need to forward any connection coming to your router on port 80 or 443 to your laptop's (192.168.x.x) corresponding ports. This is called Port-Forwarding and all routers support this. Port-Forwarding is done by logging on to the admin interface of your router (Many times its at http://192.168.0.1 or http://192.168.1.1).
But again my application is accessible at localhost? You need to make sure your apache/nginx listens on 0.0.0.0 or atleast 192.168.x.x interface. This is how computers outside your laptop will be able to make connection to your laptop on port 80/443.
My internet connection has a dynamic IP adress which keeps changing every time the modem is restarted, so I have a hard time configuring the Authorized Networks in Access Control.
This is explained at https://cloud.google.com/sql/docs/access-control#dynamicIP .
Your options are, and I quote:
Use a proxy service so that your application appears to come from only one IP address. Add this address to the authorized networks that can connect to the instance.
Use a CIDR range that covers all of the IP addresses from which your service might connect.
Use the CIDR range 0.0.0.0/0, which allows all external IP addresses to connect.
The third and last option, despite its attractive simplicity has implications that may make it undesirable -- read the docs I'm pointing to.
I'm implementing the PASV mode in a FTP server, and I send to the client the IP address and port of the data end point. This is stupid because the IP is actually where the client is already connecting, so there ire two options:
How could I get the public IP
address from a given instance? Not
the VIP, but the public one.
How could I get the original target
IP address that the user used from
a Socket object? Considering routers and load balancers in the middle :P
An answer to any of this questions would do, although there is another way that could work... may I get the public IP address doing a DNS look up of myapp.cloudapp.net?
A fourth option would be use the Azure Management API library... but, too much trouble :P.
Cheers.
Not sure if you ever figured this out, but here's my take on it. The individual role instances are all behind the Windows Azure load balancer and have no idea what the original, outward-facing IP address is. Also, there's no Management API call that returns IP address - Get Deployment returns the URL but not the IP address. I think the only option is going to be a dns lookup.
Having said that: I don't think you can host a passive ftp server in your role instance (at least not elegantly). You may open up to 25 input endpoints on your role (up from 5 - see my recent blog post about this update), but there's manual work involved in the configuration. I don't know if your ftp application lets you limit your port range to such a small number of ports. Also:
You'd have to define each port as its own input endpoint (this is the manual labor part I mentioned) - input endpoints don't allow a port range to be specified, unlike the internal endpoints.
You'd have to specify the port number that's used internally, and the port numbers would need to be sequential
One last thing on ftp: you should be able to host an sftp server with no trouble, since all traffic comes through one port.
The hack that I'm contemplating right now is to retrieve http://www.icanhazip.com/. It isn't elegant and is subject to the availability of that service, but it gets the job done. A better solution would be appreciated!