This is list of useful blogs and websites that ‘s worth taking a look :
https://packetlife.net/
https://blog.norz.at/
https://krebsonsecurity.com/
https://www.marthur.com/
https://www.fir3net.com/
https://shop.hak5.org/pages/videos
https://www.howtoforge.com/
http://www.firewall.cx/index.php
https://thehackernews.com/
Security advisories:
https://tools.cisco.com/security/center/publicationListing.x
https://support.citrix.com/search/#/All%20Products?ct=Security%20Bulletins&searchText=&sortBy=Created%20date&pageIndex=1
https://support.f5.com/csp/new-updated-articles
https://talosintelligence.com/vulnerability_reports#disclosed
https://fortiguard.com/psirt
Outages:
https://www.thousandeyes.com/outages
https://downdetector.com/
https://www.uptrends.com/tools/uptime
Tools:
ASN lookup: https://www.ultratools.com/tools/asnInfo
Speedtest: https://speed.cloudflare.com/
Looking Glass: https://lg.he.net/
Built with lookup: https://builtwith.com/
Domain tools: https://dnslytics.com/tools#domain
What is my ip: https://whatismyipaddress.com/
Security site check: https://sitecheck.sucuri.net/