I’m using the following tools to perform lossless image compression: jpegoptim – jpegoptim is a utility for optimizing JPEG files. It provides lossless optimization (based on optimizing the Huffman tables) and “lossy” optimization based on setting a maximum quality factor. optipng – OptiPNG is a PNG optimizer that recompresses the image files to a smaller…
How to block access by user agent in Nginx. In this configuration, i will use ngx_http_map_module. Inside http section: include /etc/nginx/blacklist; Inside server section (virtual host). We will return 444 status code. if ($block_ua) { return 444; } The blacklist file (example) map $http_user_agent $block_ua { default 0; ~*profound 1; ~*scrapyproject 1; ~*netcrawler 1; ~*nmap…
arp-scan is a very fast ARP packet scanner that shows every active IPv4 device on your subnet. Since ARP is non-routable, this type of scanner only works on the local LAN (local subnet or network segment). arp-scan shows all active devices even if they have firewalls. Devices cannot hide from ARP packets like they can…
Httping is like ‘ping’ but for http-requests. Give it an url, and it’ll show you how long it takes to connect, send a request and retrieve the reply (only the headers). Be aware that the transmission across the network also takes time! So it measures the latency of the webserver + network. Installing on Debian:…