Currently, I am running asp.net on a 4.0 Framework. I found one section of my code that is truly expensive for me to use. I currently get the IP Address and the reverse dns for users accessing my site, however, I am trying to keep performance in mind.
Is there a cheaper alternative to this?
return System.Net.Dns.GetHostEntry(HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"]).HostName;
Since the ServerVariables indexer returns a string, your code snippet calls the GetHostEntry string overload. Its documentation describes a three-step lookup algorithm, with two separate queries. The GetHostEntry IPAddress overload documentation doesn't describe any similar process, so perhaps it saves a query. Then again, it seems to provide the same info (all IP address and host names), so maybe it's the same, but just documented differently.
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I have built a distributed HTTP scraper solution that uses different "exit addresses" addresses by design in order to balance the network load.
The solution supports IPv4, IPv6 and HTTP proxy to route the traffic.
Each processor was responsible to define the most efficient route to balance the traffic and it was temporarily implemented manually for prototyping. Currently, the solution grows and with the number of processors as the complexity of the load balancing task get higher, that's why I need a way to create a component dedicated to it.
I did some rather extensive research, but seem to have failed in finding a solution for load balancing traffic between IPv6, IPv4 (thousands of local addresses) and public HTTP proxies. The solution needs to support weights, app-level response checks and cool-down periods.
Does anyone know a solution that already solves this problem? Before I start developing a custom one.
Thanks for your help!
If you search for load balancing proxy you'll discover the Cache Array Routing Protocol (CARP). This CARP might not be what you're searching for and there exists servers only for the proxy-cache what I never knew till now.
Nevertheless those servers have own load balancers too, and perhaps that's a detail where it's worth it to search more.
I found a presentation mentioning CARP as outstanding solution too: https://cs.nyu.edu/artg/internet/Spring2004/lectures/lec_8b.pdf
Example: for proxy-arrays in Netra Proxy Cache Server: https://docs.oracle.com/cd/E19957-01/805-3512-10/6j3bg665f/index.html
Also there exist several concepts for load-balancing (https://link.springer.com/article/10.1023/A:1020943021842):
The three proposed methods can broadly be divided into centralized and decentralized
approaches. The centralized history (CH) method makes use of the transfer rate of each
request to decide which proxy can provide the fastest turnaround time for the next job.
The route transfer pattern (RTP) method learns from the past history to build a virtual
map of traffic flow conditions of the major routes on the Internet at different times of the
day. The map information is then used to predict the best path for a request at a particular time of the day. The two methods require a central executive to collate information
and route requests to proxies. Experimental results show that self-organization can be
achieved (Tsui et al., 2001). The drawback of the centralized approach is that a bottleneck and a single point of failure is created by the central executive. The decentralized
approach—the decentralized history (DH) method—attempts to overcome this problem
by removing the central executive and put a decision maker in every proxy (Kaiser et al.,
2000b) regarding whether it should fetch a requested object or forward the request to another
proxy.
As you use public proxy-servers probably you won't use decentralized history (DH) but centralized history (CH) OR the route transfer pattern (RTP).
Perhaps it would be even useful to replace your own solution completely, i.e. by this: https://github.blog/2018-08-08-glb-director-open-source-load-balancer/. I've no reason for this special example, it's just random by search results I found.
As I'm not working with proxy-servers this post is just a collection of findings, but perhaps there is a usable detail for you. If not, don't mind - probably you know most or all already and it's never adding anything new for you. Also I never mention any concrete solution.
Have you checked this project? https://Traefik.io which supports http/2 and tcp load balancing. The project is open source and available on github. It is build using Go. I'm using it now as my reverse proxy with load balancing for almost everything.
I also wrote a small blog post on docker and Go where I showcase the usage of Traefik. That also might help you in your search. https://marcofranssen.nl/docker-tips-and-tricks-for-your-go-projects/
In the traefik code base you might find your answer, or you might decide to utilize traefik to achieve your goal instead of home grown solution.
See here for a nice explanation on the soon to be arriving Traefik 2.0 with TCP support.
https://blog.containo.us/back-to-traefik-2-0-2f9aa17be305
I am using RTI DDS 5.2.3.17 and would like to get the IP address of the remote DataReader/Subscriber that I am sending messages to, to add to some log messages.
How would I go about doing this I am having some trouble in just forming the logic of what to do?
The mechanism described for your question here, using the SampleInfo, will not work for obtaining the IP address of DataReaders
Depending on the situation, the easiest approach would probably be to install a listener on your DataWriter and inspect the last_subscription_handle parameter when the DataWriterListener’s on_publication_matched() callback is invoked. As explained in the RTI Knowledge Base article Accessing the GUID of Connext DDS Entities, the instance handle is essentially another GUID for you to inspect.
If you have many readers that you need to keep track of, it might be easier to subscribe to the BuiltinTopics used for discovery, as explained in that same KB article. That is more work though.
Again, all of this is assuming you are looking for the IPv4 address. Also note that this is not a publicly exposed mechanism, so things might change in the future. And all of this breaks at the moment that your application explicitly sets its GUID.
So, my apologies if my question in not clear, I have limited knowledge in DNS and it is possible my wording is incorrect.
A colleague, once explained me new DNS can return several ip for one host. I saw it was indeed possible with round robin, but the way I understood was to delegate the task of choosing which ip to the client. At the same time, it was possible to add a priority, or weighting to the response.
The purpose behind this was to have a first level load balancing between different zones.
I can not find more information about this, but I believe the terminology I use is incorrect.
Could you tell me more about this, or I got confused by his explanation?
Round Robin DNS
Round Robin DNS is a basic form of load balancing. Check out the wikipedia page
For an excellent explanation of how to use Round Robin DNS in a practical context see AWS's tutorial on using RRDNS with Route 53
I have a web service where i do different things according to where ones IP is from. I have a simple test application where i open a WebClient and makes it call the web service. I would like to be able to change the IP on the test application so that it "seems" that it comes from different countries (this will help me test goals in google analytics too) - is this possible - to change/simulate that my application is located in another country (France, Germany, Belgium, England, US, etc...)
It's possible to use a Proxy or an VPN Tunnel, but you'll need an End-Point in the country you want. But, there are also plenty of lists around the web for this.
The other answers more accurately provide a solution, but you could always fake it. Utilise your own small private network and provide a facade to handle IP locationing for DEBUG vs. PRODUCTION mode. All of this of course wouldn't trick Google ;-) but it would help solidify your application.
Sorry for possibly being redundant.
The obvious solution is to "bounce" through a proxy ser ver in each of the countries you wish to test for. I've had good luck in the past with sites such as proxy2free or publicproxyservers in the past.
Other solutions would involve running a client from a host in one of these countries, by way of a VPN / RDP / RAdmin-type session, but that implies owning assets or knowing people in these countries who would trust you with using their hosts in this fashion.
Another solution involves a bit of a program change in your application. By detection of a particular trigger (could be one of several different IPs but from the same country where you reside, could be some added parameter on the url such as &ctrytest=Spain etc.) your application would substitute the IP with one of several foreign IP (from the desired countries) at the level of the country detection logic in your code, but otherwise using the real IP from your client request to actually serve the application.
You probably realize it based on the previous answers, but just to be sure: IP addresses are not a certain indicator of the country a user is in. For example, I once worked in the US for a UK-based company, and we used IP addresses allocated to a UK-based ISP.
Ultrasurf may help: http://ultrasurf.en.softonic.com/
I don't think you can specify though, exactly where in the world your request is sent from.
I'm making a network game (1v1) where in-game its p2p - no need for a game server.
However, for players to be able to "find each other", without the need to coordinate in another medium and enter IP addresses (similar to the modem days of network games), I need to have a coordination/matching server.
I can't use regular web hosting because:
The clients will communicate in UDP.
Therefore I'll need to do UDP Hole Punching to be able to go through the NAT
That would require the server to talk in UDP and know the client's IP and port
afaik with regular web hosting (php/etc) I can only get the client's IP address and can only communicate in TCP (HTTP).
Options I am currently considering:
Use a hosting solution where my program can accept UDP connection. (any recommendations?)
UDPonNAT seems to do this but uses GTalk and requires each client to have a GTalk account for this (which probably makes it an unsuitable solution)
Any ideas? Thanks :)
First, let me say that this is well out of my realm of expertise, but I found myself very interested, so I've been doing some searching and reading.
It seems that the most commonly prescribed solution for UDP NAT traversal is to use a STUN server. I did some quick searches to see if there are any companies that will just straight-up provide you with a STUN hosting solution, but if there even were any, they were buried in piles of ads for simple web hosting.
Fortunately, it seems there are several STUN servers that are already up and running and free for public use. There is a list of public STUN servers at voip-info.org.
In addition, there is plenty more information to be had if you explore SO questions tagged "nat".
I don't see any other choice than to have a dedicated server running your code. The other solutions you propose are, shall we say, less than optimal.
If you start small, virtual hosting will be fine. Costs are pretty minimal.
Rather than a full-blown dedicated server, you could just get a cheap shared hosting service and have the application interface with a PHP page, which in turn interfaces with a MySQL database backend.
For example, Lunarpages has a $3/month starter package that includes 5gb of space and 50gb of bandwidth. For something this simple, that's all you should need.
Then you just have your application poll the web page for the list of games, and submit a POST request in order to add their own game to the list.
Of course, this method requires learning PHP and MySQL if you don't already know them. And if you do it right, you can have the PHP page enter a sort of infinite loop to keep the connection open and just feed updates to the client, rather than polling the page every few seconds and wasting a lot of bandwidth. That's way outside the scope of this answer though.
Oh, and if you're looking for something absolutely free, search for a free PHP host. Those exist too! Even with an ad-supported host, your app could just grab the page and ignore the ads when you parse the list of games. I know that T35 used to be one of my favorites because their free plan doesn't track space or bandwidth (it limits the per-file size, to eliminate their service being used as a media share, but it shouldn't be a problem for PHP files). But of course, I think in the long run you'll be better off going with a paid host.
Edit: T35 also says "Free hosting allows 1 domain to be hosted, while paid offers unlimited domain hosting." So you can even just pay for a domain name and link it to them! I think in the short term, that's your best (cheapest) bet. Of course, this is all assuming you either know or are willing to learn PHP in order to make this happen. :)
There's nothing that every net connection will support. STUN is probably good, UPnP can work for this.
However, it's rumored that most firewalls can be enticed to pass almost anything through UDP port 53 (DNS). You might have to argue with the OS about your access to that port though.
Also, check out SIP, it's another protocol designed for this sort of thing. With the popularity of VOIP, there may be decent built-in support for this in more firewalls.
If you're really committed to UDP, you might also consider tunneling it over HTTP.
how about you break the problem into two parts - make a game matcher client (that is distinct from the game), which can communicate via http to your cheap/shared webhost. All gamers who wants to use the game matching function use this. THe game matcher client then launches the actual game with the correct parameters (IP, etc etc) after obtaining the info from your server.
The game will then use the standard way to UDP punch thru NAT, etc etc, as per your network code. The game dont actually need to know anything about the matcher client or matcher server - in the true sense of p2p (like torrents, once you can obtain your peer's IPs, you can even disconnect from the tracker).
That way, your problems become smaller.
An intermediate solution between hosting your own dedicated server and a strictly P2P networking environment is the gnutella model. In that model, there are superpeers that act like local servers, having known IP addresses and being connected to (and thus having knowledge of) more clients than a typical peer. This still requires you to run at least one superpeer yourself, but it gives you the option to let other people run their own superpeers.