[tor-talk] Ahmia search engine works normally again

[Nurmi, Juha]

Hi,

Ahmia.fi and msydqstlz2kzerdg.onion went offline for a short while. Someone
flooded the onion site with multiple requests per second: with randomly
selected user agent strings someone was generating GET
msydqstlz2kzerdg.onion/address/<somethingherethatischanging> requests.

Constant flood was similar to this:
[07/Dec/2016:04:11:04 +0100] "GET /address/... HTTP/1.1" "OS"
[07/Dec/2016:04:11:04 +0100] "GET /address/... HTTP/1.1" "like"
[07/Dec/2016:04:11:04 +0100] "GET /address/... HTTP/1.1" "NT"

As a results, Ahmia tried to load the page /address/ over and over again
and this exhausted CPU of my front-end server.

How I fixed this:

1) I separated ahmia.fi and msydqstlz2kzerdg.onion to run
independently with their own processes
2) I disabled msydqstlz2kzerdg.onion/address/ completely,
https://ahmia.fi/address is still available
3) I adjusted several performance settings and cache
4) I added one more CPU core to the front-end server

Ahmia search engine works normally again. Still, I hope that this flood
stops.

Peace,
Juha