I would like to point the connection to my A server 25565 port to another 30000 port of B server. But I need to access the ip address of the user who sent me a connection request from B server.
I have no idea how to do it. I've directed the traffic using the proxy logic in Java, but the performance is bad.
Is there another alternative way I can use it?
iptables -t nat -A PREROUTING -p tcp --dport 25565 -j DNAT --to-destination myAnotherServerIP:30000
iptables -t nat -A POSTROUTING -j MASQUERADE
I did by adding this iptables rules. But I can't reach the IP address where the request came from. (Source IP Adress)
I don't have to do it that iptables rules. Any alternative would be a useful system or path.
There are several options to achieve that. For example:
HA-proxy
nginx TCP proxy
Both are build for high throughput and low latency and both can be configure to provide decent access information.
Related
I have a openVPN server setup on a AWS instance and I would like to use it to route traffic from my home client (client1, 192.168.0.0/24) to a client(client2, 10.81.0.0/16) on a machine on a second network through the openVPN server. I want to route the connections from client1 to client2's network so that I can connect to several devices in client2's network. However I dont have control over the gateway in client2's network so I can't add a route back to the vpn.
As far as I can tell I have the openVPN configuration setup in that once client1 and client2 are connected I can access client2 from client1, the routes are also setup so that if I ping a machine on client2's network the traffic is routed through the vpn but no response happens as client2's network devices do not know how to route the vpn ips back to client2.
I am assuming that I need to setup nat masqurading at client2 but I am unsure how to properly handle this as I am not that familiar with iptables.
tried on client2:
iptables -t nat -A POSTROUTING -o tun0 -j MASQUERADE
server.conf
port 1194
proto udp
dev tun
user nobody
group nogroup
persist-key
persist-tun
keepalive 10 120
topology subnet
server 10.8.0.0 255.255.255.0
ifconfig-pool-persist ipp.txt
client-to-client
route 10.81.0.0 255.255.0.0
push "route 10.81.0.0 255.255.0.0"
dh none
ecdh-curve prime256v1
... encryption info ...
client-config-dir /etc/openvpn/ccd
status /var/log/openvpn/status.log
verb 3
ccd/client2
iroute 10.81.0.0 255.255.0.0
For anyone with a similar issue, I found this https://arashmilani.com/post?id=53 that helped me solve the issue.
For me I needed to add the following instead of what I tried.
iptables -A FORWARD -i tun0 -j ACCEPT
iptables -A FORWARD -i tun0 -o eno2 -m state --state RELATED,ESTABLISHED -j ACCEPT
iptables -A FORWARD -i eno2 -o tun+ -j ACCEPT
iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o eno2 -j MASQUERADE
tun0 is the tunnel interface from the VPN and eno2 is the interface for client2's network. 10.8.0.0/24 is the default subnet for the VPN subnet.
The forwarding was the big issue, also the masquerade is based on the ip address range of the VPN on the output interface.
I have a service listening to customer traffic on ports 80 and 443 of eth1. The servers hosting my service also host other admin/privileged access content on eth0 and localhost
I am trying to setup iptable rules to lock down eth1 on servers which is on same network as clients (block things like ssh through eth1/ accessing internal services running on port 9904 etc.) I also want to make sure that the rules dont forbid regular access to eth1:80 and eth1:443. I have come up with below rules but wanted to review with iptable gurus on possible issues with this rule.
-A INPUT -i eth1 -p tcp -m tcp --dport 80 -j ACCEPT
-A INPUT -i eth1 -p tcp -m tcp --dport 443 -j ACCEPT
-A INPUT -i eth1 -j DROP
Do the rules above suffice
How does above differ from the rules found when googling
-P INPUT ACCEPT
-P FORWARD ACCEPT
-P OUTPUT ACCEPT
-A INPUT -i eth1 -p tcp -m tcp --dport 80 -j ACCEPT
-A INPUT -i eth1 -p tcp -m tcp --dport 443 -j ACCEPT
-A INPUT -i eth1 -p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -j DROP
-A INPUT -i eth1 -p tcp -j ACCEPT
-A INPUT -i eth1 -j DROP
thanks i got this answered in https://serverfault.com/questions/834534/iptable-rules-to-restrict-eth1-access-to-ports-80-and-443 , adding it here for completeness
The first set of rules first allow all incoming packets on your ports
80 and 443. Then it drops ALL other incoming packets (except those
already accepted).
The second set of rules first allow all incoming packets on ports 80
and 443. Then it drops incoming connections (excluding 80 and 443 that
are already accepted), which are packets with only the SYN flag set.
Then it allows all incoming packets.
The difference here is what happens to your OUTGOING connections. In
the first ruleset, if you attempt to connect to another server, any
packets that server sends in response will be dropped so you will
never receive any data. In the second case, those packets will be
allowed since the first packet from the remote server will have both
SYN and ACK set and therefore pass the SYN test, and any following
packets will not have SYN set at all, and therefore pass the test.
This has been traditionally done using conntrack which requires the
kernel to keep track of every connection in the firewall, with a
command like
-A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
that matches the incoming packet either to an existing connection, or
a connection related to some other existing connection (eg FTP data
connections). If you aren't using FTP or other protocols that use
multiple random ports, then the second ruleset achieves basically the
same result without the overhead of tracking and inspecting these
connections.
I don't know if the question is related to the topics on stackoverflow so, if not sorry in advance.
I have the following problem that I'm trying to solve :
I am connected to my university network that requires me to configure my browser to use a proxy. I want to set up a router in my house ( D-Link Dir-300 with Firmware: DD-WRT v24-sp2) and because I am using multiple Android devices that are not rooted ( I can't use global proxy apps ) I was thinking about the following solution :
Question Can I make my router redirect all the traffic from my wireless network to the proxy server that I'm using ( allowing the devices not to configure a proxy server) ?
I have a HTTP redirect tool available on the router configuration page
I looked up the destination IP address from the proxy URL that I was using and I get 4 IP addresses for that node, I tried to use two of them with the source network set to 192.168.1.0 but it didn't work -my browser on the android devices doesn't work without setting up the proxy.
____________________________________ EDIT ____________________________
After looking some more I found this link
#!/bin/sh
PROXY_IP=[IP]
PROXY_PORT=[PORT]
LAN_IP=`nvram get lan_ipaddr`
LAN_NET=$LAN_IP/`nvram get lan_netmask`
iptables -t nat -A PREROUTING -i br0 -s $LAN_NET -d ! $LAN_IP -p tcp --dport 80 -j DNAT --to $PROXY_IP:$PROXY_PORT
iptables -t nat -A POSTROUTING -o br0 -s $PROXY_IP -p tcp -d $LAN_NET -j SNAT --to $PROXY_IP
iptables -A FORWARD -i vlan1 -o br0 -s $LAN_NET -d $PROXY_IP -p tcp --dport $PROXY_PORT -j ACCEPT
How can I modify it to redirect all the traffic udp/tcp etc coming from all the ports?
Easy option is to configure your proxy on your android device. When setting up the wireless connection select advanced options and enter your proxy settings, on older android devices it's somewhat hidden but I managed to do it on a 2.3 one.
For iOS you can add it later to your wifi settings.
If you router is not the main entry point for internet (if it's secondary) you can configure it to route to your PC/laptop. Configure a static IP op your PC/laptop, share internet over there, and configure that IP as gateway on your router.
You can install a proxy tool (charles proxy for example) on your PC and configure it to forward your traffic to the internet-proxy. On your devices you still need to setup the proxy, but this time it's your PC's proxy (gateway+8080).
I have been trying to deploy a home-made server. My network consists of a router (Comtrend brand) and 2 pcs (A server laptop connected to eh0 and a netbook connected to WiFi).
The problem is that everytime I try to access to my external public IP I'm redirected to my routers internet address (192.168.1.1).
But if I access with directly with 192.168.1.132 I can see all my services published and use all the protocols. (http, ssh, etc).
What could I do? Is it a problem in the server configuration?
Configuration:
My server's ip is always 192.168.1.132
My laptop receives diferent internal ips but this is not important
My router has a dynamic ip. Let's say X.X.X.X.
Things I've already tried:
1.
I have opened ports in my router. Right now I have:
http 80 80 TCP 80 80 **192.168.1.132** ppp0.1
ssh 22 22 TCP 22 22 192.168.1.132 ppp0.1
2.
I tried with IPTABLES by adding the two next rules:
iptables -t nat -A PREROUTING -p tcp -i eth0 --dport 80 -j DNAT --to 192.168.1.132:80
iptables -A FORWARD -p tcp -i eth0 -d 192.168.1.132 --dport 80 -j ACCEPT
Then:
iptables -P INPUT ACCEPT
iptables -P OUTPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -F
You may need to change the router's http management port to some port other than port 80 (like, port 8080 for example), in order to get the port forwarding to work, so that it forwards http requests on port 80 to your server at 192.168.1.132.
I have X-Wrt based on OpenWrt 8.09 on my router
I have home LAN of few computers on which I have some network servers (SVN, web, etc). For each of service I made forwarding on my router (Linksys wrt54gl) to access it from the Internet (<my_external_ip>:<external_port> -> <some_internal_ip>:<internal_port>)
But within my local network this resources by above request is unreachable (so I need make some reconfiguration <some_internal_ip>:<internal_port> to access).
I added some line to my /etc/hosts
<my_external_ip> localhost
So now all requests from local network to <my_external_ip> forwards to my router but further redirection to appropriate port not works.
Advise proper redirection please.
You need to install an IP redirect for calls going out of the internal network and directed to the public IP. Normally these packets get discarded. You want to reroute them, DNATting to the destination server, but also masqueraded so that the server, seeing as you, its client, are in its same network, doesn't respond directly to you with its internal IP (which you, the client, not having sent the packet there, would discard).
I found this on OpenWRT groups:
iptables -t nat -A prerouting_rule -d YOURPUBLICIP -p tcp --dport PORT -j DNAT --to YOURSERVER
iptables -A forwarding_rule -p tcp --dport PORT -d YOURSERVER -j ACCEPT
iptables -t nat -A postrouting_rule -s YOURNETWORK -p tcp --dport PORT -d YOURSERVER -j MASQUERADE
https://forum.openwrt.org/viewtopic.php?id=4030
If I remember correctly OpenWrt allows you to define custom DNS entries. So maybe simply give a proper local names to your sources (ie. svnserver.local) and map them to specific local IPs. This way you do not even need to go through router to access local resources from local network.