So here is my issue, I have a website hosted from a virtual machine on my server and am using a dyndns service to point a url to my IP. My ISP recently set up a new modem which unfortunately has its own built in gateway and router. After fighting it to forward port 80 I tested it by trying to navigate to the site via the URL and it didn't work, then I tested it on my phone connected to cell data network and it worked! I am able to visit the site via the URL as long as I am not connected to my network. i find this very weird and cannot figure out why.
I am able to view the site on my network by typing in the local IP of the server.
Any suggestions why this might be occurring?
Yes, this is a pain. Usually your modem won't route traffic from inside that's destined for its public IP address.
When you come from outside, the traffic hits the modem from the external line, and the port forwarding rules get applied, and the traffic reaches your web server. But those port forwarding rules don't get applied to internal traffic. You're trying to browse the web server on the modem, rather than on your server.
I did once find a modem that allowed forwarding of internal traffic, but that was a long time ago, and I haven't see one like it since. What I do these days is to use the internal address when I'm on the internal network, and the external address when I'm not. For things that get scripted, I have a little function that determines whether I'm on my local network or not, and programmatically chooses the right way to address the server.
This is because your router does not support hairpinning (or does not have it set up).
From Cisco Support Community:-
The term hairpinning comes from the fact that the traffic comes from one source into a router or similar devices, makes a U-turn and goes back the same way it came.
Visualize this and you see something that looks like a hairpin.
Hairpin NAT is a useful technique for accessing an internal server using a public IP. Since you are using a public IP to attempt to access a server in your network, the traffic will attempt to go out to the internet. In order to reach the server, the traffic will need to be redirected to the correct location.
The problem is how you are doing your internal routing DNS.
You can do DNS Lookup and trace route to see where the Website name is not resolving and whether if you ping the domain e.g. ping something.com return the public IP.
I resolved ours by doing policy routing on website FQDN to go through a different WAN. It's working fine. This works for those with different WAN terminating at the site.
The other way is redo the DNS configuration in internal network.
Related
I'm struggling to get my AzerothCore Docker instance to allow logins via the internet when using a domain instead of an IP address. My ISP only offers dynamic IPs so I'm using dynu for simplicity.
If Realmlist set to domain in acore_auth.realmlist I can connect over LAN but external connections get stuck at realm select screen. However if I change the realmlist to just my external IP it works for both so doesn't look like a firewall issue.
The domain is working with webserver hosted on the same machine so that can't be the issue. Any ideas?
I don't know exactly the reason why this fixed it, but I tweaked some of my pfSense settings for DNS resolution (removing my domain from the overrides) to get it going. Hopefully this might be useful to someone else!
I am having below two issue,
The below one observed from IFTTT make an web request,
1.Applet skipped "If You say "Open Binny", then Make a web request".Unable to make web request: Error: ETIMEDOUT
"I am using this URL http://192.168.43.184:8123/api/services/shell_command/test_cmd?api_password=solo#123"
The below one is observed in home assistant while we call service
2.homeassistant.components.shell_command] Error running command: pwd, return code: 1
can you solve this ? Thanks
The IP (192.168.43.184) you are using in your http-request is a private internal IP (it will only work wthin your home network). You need to use your public (external) IP from your internet router (hopefully you have a public one). But even then, it will not work until you configure your router for a port forwarding, so if a request hit's your external IP (and port) your router should know which server (here 192.168.43.184) should be reached. You need a port forwarding like this: If a TCP conncetion comes to your public IP on port 8123 route it further to 192.168.43.184:8123
But I would suggest to get a DNS-entry like from DynDNS.org because your public IP will maybe change, and then you always have to adapt the IFTTT-URLs. With an DNS-entry you get rid of changing all the URLs out there. Often there is a tool which runs in your lokal network and checks if your public IP has changed and informes DNS-provider and updates the mapping between your DNS entry and your public IP
You need a secure remote connection. You can use duckdns and https cert created with dehydratated
https://www.splitbrain.org/blog/2017-08/10-homeassistant_duckdns_letsencrypt
You can try the new tutorial https://www.home-assistant.io/integrations/google_assistant/ for google assistant connection
I know in airports, for example, I've connected to their AP, and it pops up a browser window to log in on my device. Is it possible to do so with NodeMCU in lua, or even with c firmware?
This can accomplished by setting the DNS server for a connecting client [via DHCP] to a sort of DNS proxy. It doesn't need to be a fully featured DNS server, it only needs to be able to either return a static DNS answer for any host name query or forward the request to a real DNS server, to resolve host names as usual.
The static answer effectively hijacks web requests at the DNS level, by forging the DNS answer, causing all host names to resolve to the IP address of a local web server. That local web server ignores any Uri details and serves a login prompt for every request. It must also maintain a list of client MAC addresses that have authenticated.
NodeMCU does have a built-in DHCP server, as part of it's built-in WiFi AP, but running both a web and a DNS proxy in ESP8266's limited memory would be a hell of a trick. I think that two of them working cooperatively, interfaced using the SPI bus might be workable... maybe even three of them, one dedicated to maintaining the list of authenticated MACs, expiring them, etc.
Note that the only part of this I have done on an ESP 8266 is some very simple web server functionality, so it's mostly theory. If you try it I'd be very interested in hearing about it. :-)
You might want to try out CaptiveIntraweb project (https://github.com/reischle/CaptiveIntraweb) which is based on NodeMCU.
There is also thread (http://www.esp8266.com/viewtopic.php?f=32&t=3618) on ESP8266 community forum that discusses the solution details.
This seems to have something to do with the subnet/availability zone, but I'm new to using a VPC and it's eluding me.
VPC: 10.80.0.0/16
subnet: 10.80.1.0/24 (us-east-1b)
subnet: 10.80.2.0/24 (us-east-1a)
All instances are Windows Server 2012.
I have an internet facing ELB created within my VPC (10.80.0.0/16). There is one instance added from AZ us-east-1a, which is on subnet 10.80.2.0/24. The instance is running IIS 7.5, with an app running on port 80 and /health.aspx set up for use as the ELB health check.
Internal traffic on the VPC is flowing normally (unrestricted). I can request health.aspx from this instance from another instance in us-east-1b (10.80.1.0/24). I can also copy files from one instance to another.
Outbound traffic is unrestricted. I can RDP to the instance (when connected to our VPN) and open a browser and request a web page and get it.
The ELB says the instance is healthy and I can see the requests to health.aspx in the IIS logs. Both the ELB and the instance are configured with a security group that allows 80 and 443.
But if I try to request {elb-url}/health.aspx over the open internet the request just times out. Similarly, with an elastic IP associated to the instance, a request to {elastic-ip}/health.aspx times out.
#Chris, thanks for the response...as it happens, I've already worked it out with some help from a friend. I'll post my findings here for posterity (in case anybody else was similarly confused about how ELB works).
This would be more clear with a diagram. But the summary is that in each availability zone, you need to create both a public and a private subnet. When you add availability zones to your ELB, you need to select the public subnet for the zone. This had already been done in us-east-1b before I got to this setup, and I had simply missed this nuance of ELB configuration. So for the new availability zone, I had to do this...
us-east-1c
private subnet 10.1.3.0/24 (using nat instance as default route)
public subnet 10.1.4.0/24 (using internet gateway as default route)
Then my instance goes in the private subnet as expected.
And the lynch pin of this whole thing is (drum roll....)
When I add us-east-1c to my ELB, I have to select the public subnet...10.1.4.0. Otherwise the instances will pass the health check (since the ELB can communicate with any instance within my entire VPC) but the responses from the servers cannot make it back out to the public internet.
This is what is so confusing. And I still don't fully understand it. The instance can make a request for, say, www.google.com. I can RDP to it and open a browser and get the web page. But a request from a host (like my laptop at my house) will die. strange.
PS: another note...make sure you are using enough NAT instance for your load. I think we ran into an issue where our NAT instance simply ran out of ports because too many web servers were trying to route outbound connections to 3rd party APIs through it. Quite honestly, I'm not good enough at this level of network/OS troubleshooting to be sure. But my theory is that our 8 instances of IIS were holding too many connections open to the NAT instance. We were also abusing the NIC on that micro instance. I upped us to two large instances, one per AZ and things smoothed back out. Both NAT instances are humming and we're not seeing the hung processes in IIS anymore.
Debugging this kind of issue is always a challenge. I have a few ideas to suggest based on what you have written (and generally apply to trying to solve this problem) that come from dealing with this a number of times.
Have you checked both the security groups and network ACLs? Bear in mind that all network ACLs need to be specified in both directions, as they are stateless. Also bear in mind that ELBs are a bit unique in this regard. While they are associated with your VPC, they sometimes need extra rules to ensure connectivity. In the past I have debugged this by opening all network ACLs on all ports, then removing these rules until it has stopped working in order to identify where the block was.
Security groups should be checked too. They are stateful but ensure that your load balancer has permissions to be hit from the web.
Have you checked this isn't an application configuration problem? I don't know how IIS comes out of the box but I would check it is setup to respond to all hostnames.
Check the ELB isn't an internal one, as that wouldn't be publically addressable.
You say the ELB is configured with the health check, but it's worth checking you also have the listener setup for port 80? It's in a separate tab on the dashboard and you will need this in addition to the health check for connectivity through the ELB.
Hope one of these tips is useful to you.
I'm using the Play Framework which uses http://localhost:9000 by default. I'm also trying something with Twitter and it needs to use a callback url for authentication, but Twitter won't accept http://localhost:9000 as a callback URL.
How can I configure my localhost to map to something like http://mylocal.loc, (similar as with an Apache vhost), instead of http://localhost:9000?
The problem is that the URL needed to be entered in the following format:
http://127.0.0.1:9000/twitter-callback
The above works perfectly as a Twitter callback address.
Twitter isn't trying to access localhost directly, it simply takes the above address as far as I understand, sticks it into the HTTP response header, prompting whichever browser being used to perform a straight forward 302 redirect.
The following blog post had some invaluable information in regards to this question:
http://www.tonyamoyal.com/2009/08/17/how-to-quickly-set-up-a-test-for-twitter-oauth-authentication-from-your-local-machine/
The reason that twitter can't use localhost as a callback url is because localhost is a redirect to your computers loopback interface. In other words, localhost is always the computer that you're on. In order for other computers (including twitter) to access your host, you need to use an external IP address, or a hostname.
To get your IP address, visit whatsmyip. This will tell you your external IP address (which other computers on the internet can access). If you have a static IP address, you can purchase a domain name, or get a free one from something like no-ip or dyndns to make it easier to remember and type. You'll need to point a DNS record from that domain to your IP. You'll also probably need to do some port forwarding and stuff to get it to go to your computer on port 9000, rather than your router (dependent on your network setup).
Possibly an easier option would be to obtain a free hosting/domain service whilst you're testing.
EDIT: josef's problem was not related to the absence of internet access to his local server, see his own answer for what was going on and a solution. This answer handles the case where a local server needs to be visible from the internet.
localhost, aka 127.0.0.1 is the name that on each computer points to the computer itself. So Twitter looks at itself, obviously doesn't see the service, end of story.
If your computer is connected to a local network, most likely that network is NATed and using private addresses like 192.168.x.x, 10.x.x.x or 172.16x.x.x. These addresses are private (not known outside of the local network because not routed on the internet), so that doesn't help you either.
What remains is your public IP address, ie the address your router gets from your ISP. Via DNS you can map that address to a name, a free service that allows you to map a fixed name also to a variable address is DynDNS.
But wait, there is more! Your router protects your network by not allowing traffic originating OUTSIDE the private network IN, unless you define some forwarding rule in the router, in your case a rule that forwards incoming tcp traffic on port 9000 to your machine's port 9000.
Once all that has been taken care of, your computer will be accessible from the outside, and your callback should work.
Edit your hosts file and add the following line:
127.0.0.1 mylocal.loc
For Windows, it is located in C:\Windows\System32\drivers\etc\. On *nix, you can find it in /etc.