Scuttle

Scuttle is a tool that lets you control the output when your server is tracerouted. It currently supports both ICMP and UDP traceroute.

Setup

You'll need a set of IP addresses you can control the reverse DNS entries for, and a Linux server that supports IP spoofing.

Vultr will let you buy as many IPs as you want, and control their reverse DNS entries, for $3/month each. AWS EC2 will let you spoof IPs – make sure you enable all inbound UDP and ICMP traffic, and disable the source/dest check (in the console, right click => Networking => Change source/dest check). Note that us-west-2 (Oregon) has unreliable route lengths, which breaks scuttle, but us-west-1 (N. California) works fine.

Run the following commands on your server, to disable kernel-level ICMP and UDP replies:

# Disable the kernel's responses to ICMP echo packets, which would interfere with our own replies.
sudo echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all

# Prevent the kernel from sending "destination port unreachable" messages, which would interfere
# with our UDP traceroute implementation. FreeBSD has a blackhole sysctl that would do this for
# us, but on Linux we don't have as much luck, so have to resort to this hack.
# Allow all outbound ICMP packets except "destination port unreachable".
sudo iptables -A OUTPUT -p icmp -m icmp ! --icmp-type port-unreachable -j ACCEPT

# Drop all outbound "destination port unreachable" packets except those sent by root.
sudo iptables -A OUTPUT -p icmp -m owner ! --uid-owner root -j DROP

Add the IPs you'd like to a newline delimited file named redirect_ips.txt, for example

123.1.1.1
123.1.1.2
123.1.1.3

Usage

Run sudo python scuttle.py redirect_ips.txt to serve responses infinitely.