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A strange process name on a Linux server does not automatically mean the server has been compromised. Neither does finding an unfamiliar file under /tmp or The real question is whether the process, file, account, location, timestamps, command line,…
Killing a malicious process does not necessarily remove malware from a Linux server. We learned this during an investigation of a compromised Zimbra mail server running on Ubuntu. We discovered suspicious processes named javab and idle. We terminated them, but…
Running your own mail server means that when something goes wrong, you sometimes need to investigate far beyond whether Postfix, LDAP, or the mailbox service is running. In this case, we were troubleshooting a production Zimbra Collaboration server running on…
Upgrading an Ubuntu server from 22.04 LTS to 24.04 LTS is normally straightforward using do-release-upgrade. However, the upgrade can fail when the server has third-party repositories, old package sources, or a DigitalOcean mirror configuration that the Ubuntu release upgrader cannot…
DNS steering systems change over time. Operators add new endpoints. Health state changes. A new region goes online. A failed site needs to be removed. A routing rule is updated. A fallback path is changed. An ASN is moved from…
Authoritative DNS must answer quickly. When a recursive resolver asks for a DNS record, the authoritative DNS server should not perform heavy work before replying. It should not rebuild routing policy during the query. It should not call several external…
DNS steering should not return an endpoint only because it is nearby. It should not return an endpoint only because a policy prefers it. The endpoint also needs to be usable. This is where health checks matter. Health checks help…
