What I want to know :
When my computer keeps one network method and asks for a renewal and extension of its current address lease to the same DHCP server, Can my computer fail to renew the lease?
If this can occur, When? and Why?
My situation
I'm trying to keep a audio-streaming to a server which has a dynamic IP.
And use UDP.
So if this server fails to extend its current address, Clients will throw packets(audio-data) to somewhere strange.
Related
I never used VPNs, I know what they are and how they work in general, but I never had to use one in practice; now I need to use it to connect to a machine in my university lab, my teacher provided the configuration file and the other needed files to set it up.
I installed the OpenVPN GUI with admin privileges, I imported the config file (".ovpn" file in my case) and launched (always as admin) the connection, which immediately works and I am assigned a new IP address. However, if I quickly check on "whatIsMyIP.com" or on Google, the IP is unchanged, it's still my original IP.
Now I also tried with other random VPNs downloaded from VPNBook, and they work, meaning that I can see that the IP changes as soon as I turn them on. I really cannot understand what I am doing wrong (my professor told me that he tried connecting through a VPN as well and it worked for him, so the problem must be on my client side)...
PLUS: when this problem of the unchanged IP is fixed, I am supposed to use ssh to connect to the remote machine. I was asked to generate a pair of public+private keys, passed the public to my teacher who added it on the machine and then connect through the command:
"ssh username#hostname"
Besides the fact that it does not work due to the VPN not changing the IP, I get the error "No address associated with hostname", so I understand it cannot resolve the given hostname, nonetheless my professor gave me only that: is it correct that I can ssh to the remote machine by only having the hostname or (as I believe) I also need the IP, which I can associate with the hostname and then connect?
I'm having trouble connecting to an Active Directory server from my computer and server. I get "The server is not operational" error when trying to connect. The server I'm trying to connect to is in a different country than me.
LDAP Url is in the usual format:
LDAP://ip_address:389/CN=Users,DC=domain_name,DC=local
I've added the application that connects to the AD to the firewall (even disabled the firewall briefly to test) and added the IP to my hosts file but I can't seem to get past the error.
Now usually at this point, I would conclude that the issue is on the AD server side (or their server firewall) that is blocking requests from our server, however, the person in charge of the AD server has tested the same LDAP url using the same utility I'm using from an external network in their country and is able to authenticate without issues.
Any ideas on what we can try next?
Ok, it turns out the client's ISP was blocking international traffic over port 389. They had to write a letter to request the ISP to allow international traffic over that port. It is now working after they've done that.
Didn't know ISPs block traffic, but I suppose ISPs for corporate clients might as in this case.
Newbie programmer here. I'm building an app for an API that requires an IP address for authentication. Basically, users have to send the API management their IPs and then each time a computer makes a request to their server, it verifies whether it's coming from a registered IP.
Since I work in a number of different places and thus end up with different IPs, I thought it would be easiest to use DynDNS to establish a URL that points to whatever my current IP is and then send that URL to the API management. So my first question is if this approach would in fact work?
Secondly, assuming this would work, I set up ben.dynalias.com and downloaded the DynDNS Updater client. It appears to be working: the updater says status: OK and displays my current IP. However, when I navigate to the URL (ben.dynalias.com) there's no response. Should this be the case? How can I tell if it's working?
I don't see any reason it shouldn't work as long as your updaters aren't overwriting each other by running at the same time automatically from different locations.
You can ping ben.dynalias.com and see if your current ip matches.
I just hosted ben.dynalias.com and it gave me your IP.
Since there is no web server running on that IP, then your browser will not be able to show you a page result.
You can use http://www.kloth.net/services/nslookup.php
to check and see if you get the correct IP from a host lookup.
Depending on how often your IP changes this might not be a great solution as the DNS will cache your hostname and will not try and resolve it again until the TTL expires normally minimum 1 hour.
whether the API management accepts a hostname instead of an IP address is a question only they can answer. Some will, many won't as it's "easier" to hijack a domain name than to hijack an ip address.
trying to browse to you-address.dynalias.com that points to your own public address rarely works, even if you opened up the right ports because your router will be highly confused. The best way to test such a setup is by using a phone or tablet with 3g/GPRS internet - of course after you set up port forwarding in the router to point the appropriate port to your computer.
I am coding a mac app, which will be a server that serve files to each user's mobile device.
The issues with this of course are getting the actual ip/port of the server host, as it will usually be inside of a home network. If the ip/port changes, its no big as i plan to send that info to a middle-man-server first, and have my mobile app get the info from there.
I have tried upnp with https://code.google.com/p/tcmportmapper/ but even though I know my router supports upnp, the library does not work as intended.
I even tried running a TURN server on my amazon ec2 instance, but i had a very hard time figuring how what message to communicate with it to get the info i need.
I've been since last night experimenting with google's libjingle, but am having a hard time even getting the provided ios example to run.
Any advice on getting this seemingly difficult task accomplished?
The port of your app will not change. The IP change could be handled by posting your servers IP to a web service every hour or whatever time period you want.
Server should run a URL http://your-web-service.com/serverip.php?ip=your-updated-ip and then have your serverip.php handle the rest (put it into a mySQL db or something)
When your client start it should ask your site for the IP and then connect to your server with that.
This is a pretty common way of handling this type of things.
To keep things simple, please allow the "assumption" that some code requires the use of a full URL, even though the domain is on the same server, i.e. a simple file path cannot be used.
TCP/IP?? Question:
If a form action target = "http://this-full-URL.com/postdata" (for example) and that URL is also on the same server, then which happens first?
A) Data is sent "out onto the web", and then returns to the same server,
or
B) Before sending any (possibly sensitive) data, the server (Linux, Apache, PHP), first "discovers" the target address is local, so (clearly) no data is sent over the net?
Thank you.
The correct answer is always A. :-)
It just happens that the case where the browser and the server are running on the same machine, "the web" will be short-circuited by the local TCP/IP stack. However, Apache and PHP are not involved in that decision; it's pure functionality of the OS networking stack.
However, if your server is behind a NAT gateway or firewall and the DNS name is resolving to the NAT gateway/firewall, the request will be routed to the NAT gateway/firewall and back to your machine. Thus, in order for the routing to stay on the same machine, the DNS name of the host of the target URL has to resolve to the actual IP address of the server machine, not be tunneled to it.
The network software will resolve the hostname to you machine, then the local TCP stack will route the request locally. Traffic won't ever leave the machine, it'll all be in memory on the server.