Who is visiting my server?
At the moment I am using the following resources to enrich my logs with ASNs and AI crawlers data:
There is some work to be done to find other sources but for now this is the most straightforward approach for me.
ASN Handle does not necessarily mean that that org is hitting my server. Some ASNs are just ISP or hosting providers.
ASN
AI Crawlers
AI Crawlers are identified by IP ranges.
ASN in Auth Logs
Many ASs are seen not only in server logs but in auth and firewall logs as well.
auth logs catch logging attempts that use different users.