KB: R script sample

coupon <- c("A","B","C","D")

generate_set<-function(coupon_set,i,n){
  if(i==n){
    cat(coupon_set)
    cat("\n")
  }else{
    for(c in coupon){
      generate_set(paste(coupon_set,c,sep=""),i+1,n)
    }
  }
}

sink("d:/temp/q6_10.txt")
generate_set("",0,10)
sink()

q6<-read.table(file="d:/temp/q6_10.txt")
q6$win<- grepl("A",q6$V1) & grepl("B",q6$V1) & grepl("C",q6$V1) & grepl("D",q6$V1)
summary(q6$win)
sum(q6$win)/nrow(q6)

KB: Simple Line Chart in R

x=seq(-10,10,0.1)
y2=x^2
y3=x^3

plot(
  x=x,
  y=y2, type="l", ylim=c(-100,100), col="red", ylab="f(x)"
)
lines(x,y3, type="l", ylim=c(-100,100), col="blue")
legend("bottomright",c("f(x)=x^2","f(x)=x^3"), lty=c(1,1), col=c("red","blue"))

HOWTO: OpenWRT and Fiddler for HTTP and HTTPS Transparent Proxy traffic capture – Part 2

Goal:

  • Setup a Hyper-V test lab for capturing traffic from an Android client.
  • Use OpenWRT as the routing gateway for the private VM network and Transparent Proxy HTTP and HTTPS traffic to Fiddler.
  • Config Fidder for traffic capture.

See Also:


Configuring OpenWRT for Transpart Proxy

  • Create Port Forward / Pre-routing rules for TCP port 80 and 443 to forward traffic to Fiddler.
    • Assuming Fiddler is running at 192.168.1.2, port 8888 for HTTP proxy and 8443 for HTTPS proxy.
    • Exclude the Fiddler machine from the port forward.


  • Create Source NAT / Post-routing rule


     

  • OR write the rules in the Firewall Custom Rules page.


     

Configuring Fiddler for Transpart Proxy

  • Enable “Allow remote computers to connect” in Fiddler Options and open corresponding ports in the Windows Firewall.


  • Use the command “!listen 8443 your_dummy_CN” to make Fiddler to listen to port 8443 for HTTPS proxy.
    • The dummy CN value is important. Without the CN value Fiddler will not handle the HTTPS handshake.


  • Use the command “prefs set fiddler.network.https.SetCNFromSNI true” to make Fiddler to generate the cert with CN to match the incoming request.

HOWTO: OpenWRT and Fiddler for HTTP and HTTPS Transparent Proxy traffic capture – Part 1

Goal:

  • Setup a Hyper-V test lab for capturing traffic from an Android client.
  • Use OpenWRT as the routing gateway for the private VM network and Transparent Proxy HTTP and HTTPS traffic to Fiddler.
  • Config Fidder for traffic capture.

See Also:

Notes on the OpenWRT installation

The OpenWRT installation basically follows the guide at https://miracoin.wordpress.com/2014/05/28/openwrt-in-hyper-v/. Here a few more tips for building the Hyper-V image:

  • Configure the Hyper-V virtual switch for the connection to the physical network and a private virtual machine network to the VM.

  • Create a new Hyper-V machine with the following settings:
    • 1 virtual processor and 64MB memory (You don’t need too much power for OpenWRT)
    • 2 Legacy Network Adapters (This is important. There’s no driver for the standard Network Adapter)
    • Bind the adapters to the physical and private virtual network.

  • Create the OpenWRT disk image