Communication between two servers for a ddos challenge page? - php

I need to develop a challenge page much similar to the Cloudflare firewall challenge.
I know how to make the front end and the back end of the challenge app and I know how to set it up on the server.
The problem comes on how to implement it to the website which is on one server, while the challenge app is on another server. How should I make the communication between the servers? Both servers will be Ubuntu 16.4. Thank you all in advance.

I think it's better to solve this issue like cloudflare using nginx server.
Make an nginx reverse proxy with rate limit
if limit hit user will be redirected to error page
integrate your challenge app with the error page.
more about this configuration is here:
https://serverfault.com/questions/645154/how-to-redirect-to-an-other-link-when-excess-request-limit-req-with-nginx
And How to use PHP in error pages is here:
Nginx, PHP + FPM Custom Error Pages
you can run this reverse proxy on third server or you can run it on the challenge app server.
make your domain points to the reverse proxy
then
make nginx config
server {
listen 80 default_server;
server_name *.*;
client_body_timeout 5s;
client_header_timeout 5s;
location / {
proxy_set_header Host $host;
proxy_pass http://00.00.00.00/; #replace with upstream ip
}
}
you have to combine this with custom php error page

Related

There is mismatch between HTTPS indicated on the server and client

This is the warning when I open my phpMyAdmin's login (index) page:
There is mismatch between HTTPS indicated on the server and client.
This can lead to non working phpMyAdmin or a security risk.
Please fix your server configuration to indicate HTTPS properly.
The error should be caused by a loadbalancer in between my client and phpmyadmin itself. SSL terminates on the loadbalancer so the URL being used (that phpmyadmin receives in request headers, I assume) is https://mydomain/phpmyadmin.
The loadbalancer communicates with phpmyadmin via http, so the URL being used between lb and pma is http://mydomain/phpmyadmin (not https).
I found this very fitting article on github: Possibility to deactivate SSL connection #170 which is for Docker containers and describes an env var to be passed to the container called "PMA_ABSOLUTE_URI" to fix the problem.
Which setting would this be in phpmyadmin NON Docker?
Any other solution to my problem is also highly appreciated.
Sidenote: Phpmyadmin works fine after the login. You can log in, there are no warnings after the log in and you can perform all interactions without problems. I am just worried about the warning.
I have exactly the same setup as you are describing. A front load balancer acts as reverse proxy and also as SSL/TLS terminator. The LB talks in plain http with the backend server where phpMyAdmin is running.
When I upgraded from 4.0.4.1 to 4.9.0.1 I got the same warning appearing at the phpMyAdmin login screen as you. I was able to solve this on the reverse proxy by "faking" the protocol from http to https. In my case my reverse proxy is a Nginx web server and just before I'd pass to the backend server, I added X-Forwarded-Proto:
server {
listen 443;
server_name my.phpmyadmin.example.com;
[... log and ssl settings ...]
location / {
include /etc/nginx/proxy.conf;
proxy_set_header X-Forwarded-Proto https;
proxy_pass http://backendserver;
}
}
By adding proxy_set_header X-Forwarded-Proto https; this tells the backend server that the client to proxy communication happens over https. Without setting this header, phpMyAdmin probably identifies (not sure, just a guess) that it was loaded on a https:// URL yet the communication (between reverse proxy and phpMyAdmin server) happened over http. Therefore it's a correct warning to be shown.
As soon as Nginx was reloaded, the warning disappared from the phpMyAdmin login screen.

php forward visitor ip to nginx

i am trying to send real visitor ip to nginx from php
this is the situation
server A - exmaple.com/a.php
server B - example/file.txt
when access exmaple.com/a.php it download file.txt located on server b
but nginx logs show server A ip as requested download, i guess that correct cause the file.txt downloaded via a.php located on server A
so how can i send the ip of the visitor instead of the server to nginx
i already have this in my nginx config
proxy_set_header X-Real-IP $remote_addr;
thank you
Server A: add X-Real-IP header with client's IP to outgoing request. This part depends on you code. For example, if CURL, you need to add curl_setopt($ch, CURLOPT_HTTPHEADER, [ 'X-Real-IP: '.$_SERVER['REMOTE_ADDR'] ]).
Server B: you need to configure nginx. Add to nginx's server config block:
set_real_ip_from SERVER_A_IP;
real_ip_header X-Real-IP; (not required because default value)
You would need to add it to your request headers.
$opts['http']['header'] = 'X-Real-IP: ' . $_SERVER['REMOTE_ADDR'] . "\r\n";
You would also need to configure Nginx to accept this, with set_real_ip_from config directives.
A better option would be to use cURL (see #Terra's answer), which gives you a bit more flexibility than the fopen wrappers.
The best option however is just to let Nginx do this. It's far more efficient than piping all this data through PHP. Use proxy_pass.

Reverse Proxy Specific Request

I have high load website, my system runs out of memory in peak times. I want to split the load so the read operations which happens to be on specific URls move to another server.
I am using nginx and php-fpm, how do I redirect specific URLs to be processed by PHP-fpm on a different server?
This is the blue print of my requirements.
location /feed/generate {
use php-fpm on a different server
}
location / { #all other requests
use existing php-fpm
}
Setup php-fpm on the second server listening on an externally accessible IP (not 127.0.0.1) port 9000.
The IP address should be private (not routed to the internet) and/or configured to only allow connections from trusted hosts (firewall).
upstream feed_php_fpm {
server <other server ip>:9000;
}
upstream local_fpm {
server 127.0.0.1:9000;
}
location /feed/generate {
fastcgi_pass feed_php_fpm;
include fastcgi.conf;
}
location / {
fastcgi_pass local_fpm;
include fastcgi.conf;
}
Please understand what you are doing and the implications of php-fpm listening on a network port vs file socket.

Load balancing dynamic php site using nginx

I have three servers. One for load balancing other two for serving web application. My load balancing works fine if i use my web page as static site. but when i log into my web page it does not respond correctly because every time it changes its server when the page loads. how can i do it without changing current server before log-out. My load balancing server configuration is
upstream web_backend{
server 192.168.33.2;
server 192.168.33.3;
}
server{
listen 80;
location / {
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass http://web_backend;
}
}
You can use Session persistence feature of nginx:
If there is the need to tie a client to a particular application
server — in other words, make the client’s session “sticky” or
“persistent” in terms of always trying to select a particular server —
the ip-hash load balancing mechanism can be used.
With ip-hash, the client’s IP address is used as a hashing key to
determine what server in a server group should be selected for the
client’s requests. This method ensures that the requests from the same
client will always be directed to the same server except when this
server is unavailable.
To configure ip-hash load balancing, just add the ip_hash directive to
the server (upstream) group configuration:
In your case just add ip_hash into your upstream definition
upstream web_backend{
ip_hash;
server 192.168.33.2;
server 192.168.33.3;
}

CakePHP Force SSL - env('HTTPS') always null

I've tried quite a few different solutions (here, here, here, here) but almost all of them caused either 404 or infinately loops.
Finally I found this question which seems to get the closest to working; but it also causes an error in Firefox when I try to load one of the actions I wish to require SSL on:
The page isn't redirecting properly
Firefox has detected that the server is redirecting the request for
this address in a way that will never complete.
This problem can sometimes be caused by disabling or refusing to
accept cookies.
Finally through a bunch of debugging I have found that env('HTTPS') always returns null for some reason (as does $this->RequestHandler->isSsl(); and $_SERVER['HTTPS']) even when I'm using an HTTPS connection. I cannot understand why this is happening, since my browser reports that I am SSL secure and my certificate seems to be installed correctly.
More Info
nginx server
listen 80;
listen 443 ssl;
ssl_certificate /etc/ssl/certs/domain.chain.crt;
ssl_certificate_key /etc/ssl/private/domain.key;
...
App Controller
var $secureItems = array('login', 'edit', 'viewDocs');
function beforeFilter() {
$this->Auth->allow('index', 'display');
$this->set('loggedUser', $this->Auth->user());
$this->__checkSSL();
}
__checkSSL() and supporting functions are directly from the previously link question (this one).
Pages load fine in HTTP and HTTPS as long as its not one of the actions I have listed in $secureItems as soon as I go to one of those actions (either HTTP or HTTPS) it infinately redirects.
Any help is appreciated!
Edit:
I am pretty sure the issue is an infinite loop caused by env('HTTPS') always being null. Since its null the check condition is always false and makes it redirect to an HTTPS URL even though its already on one.
Is there another way I can check for HTTPS or can someone tell me why env('HTTPS') is always returning null?
You're edit is a step in the right direction...
It is down to the web server to set environment variables such as $_SERVER['HTTPS'].
If this has a no value, you need look no further than the web server - nginx in your case - or at any web servers inbetween (reverse proxies, etc.)
I don't have any experience with SSL on nginx in particular, but from what I can gather you need to make sure nginx is sending fastcgi_param HTTPS on for connections on port 443.
Adding something like this, perhaps:
server {
listen 443;
server_name example.com;
ssl on;
fastcgi_param HTTPS on;
# ...
}
Search for "nginx fastcgi_param HTTPS" for other config examples.
I also found some other variables that may be of use further down the line.

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