[{"content":"How I Solved the Distrobox Confusion in My Terminal Recently, I found myself struggling with something that seemed like a simple problem: when I was working with multiple terminal windows, I could never remember which one was inside a Distrobox and which one was on my local system. If you\u0026amp;rsquo;ve ever juggled between different environments, you know exactly how annoying this can get.\nSo, I decided to create a quick plugin for my favorite terminal prompt, Spaceship, that would clearly indicate …","date":"2026-01-04","permalink":"/posts/spaceship-distrobox/","summary":"How I Solved the Distrobox Confusion in My Terminal Recently, I found myself struggling with something that seemed like a simple problem: when I was working with multiple terminal windows, I could …","tags":null,"title":"Spaceship Distrobox"},{"content":"Understanding the Google Groups Spam Problem Over the past year, I\u0026amp;rsquo;ve noticed a significant increase in spam messages originating from Google Groups. This issue stems from the way Google Groups is designed: It gives spammers an easy way to distribute large volumes of unwanted mail using legitimate Google mail servers, which makes filtering much harder.\nWhy it Happens There are a few fundamental problems with how Google Groups works that make it particularly attractive to spammers:\nNo …","date":"2025-10-10","permalink":"/posts/google-groups-spam/","summary":"Understanding the Google Groups Spam Problem Over the past year, I\u0026rsquo;ve noticed a significant increase in spam messages originating from Google Groups. This issue stems from the way Google Groups …","tags":null,"title":"Google Groups Spam"},{"content":"Recently, I had to deal with a serious problem: backscatter.\nOne of our mail gateways ended up listed on the backscatter.org blacklist for sending bounce messages to forged senders.\nAfter checking the logs, I quickly realized that our system wasn\u0026amp;rsquo;t actually protected against backscatter attacks, so I had to do something about it.\nWhat Even Is Backscatter? Backscatter is unwanted email that your mail server sends after receiving a message, usually in the form of a non-delivery report (NDR) …","date":"2025-08-01","permalink":"/posts/blocking-invalid-rcpt-postfix/","summary":"Recently, I had to deal with a serious problem: backscatter.\nOne of our mail gateways ended up listed on the backscatter.org blacklist for sending bounce messages to forged senders.\nAfter checking the …","tags":null,"title":"Blocking Invalid Recipients Before They Reach Your Exchange Server"},{"content":"Understanding dovecot.index.cache I recently migrated an old mail server system into its new home. After the migration, I checked the logs and noticed some warnings that looked like this:\nMay 17 11:23:13 server1 dovecot: dsync-local(user@domain.tld)\u0026amp;lt;cRjZCwGnKWiIvicA2dm5Tw\u0026amp;gt;: Error: Mailbox INBOX: mmap(size=511310568) failed with file /var/vmail/domain.tld/user/Maildir/dovecot.index.cache: Cannot allocate memory The error indicates that the dovecot.index.cache file is too big to process, and …","date":"2025-05-18","permalink":"/posts/dovecot-index-cache-issues/","summary":"Understanding dovecot.index.cache I recently migrated an old mail server system into its new home. After the migration, I checked the logs and noticed some warnings that looked like this:\nMay 17 …","tags":null,"title":"Dovecot Index Cache Issues"},{"content":"Welcome to My Blog! I’m Demian, a Sysadmin, Email Infrastructure enthusiast, and a passionate Open Source contributor. This is where I’ll be sharing what I know about system administration, managing email infrastructure, and contributing to open source projects.\nWhat to Expect On this blog, I’ll be writing about:\nSysadmin tips and tools: Everything I’ve learned managing servers, networks, and infrastructure. Email Infrastructure: Best practices for setting up, securing, and managing email …","date":"2025-05-11","permalink":"/posts/my-first-post/","summary":"Welcome to My Blog! I’m Demian, a Sysadmin, Email Infrastructure enthusiast, and a passionate Open Source contributor. This is where I’ll be sharing what I know about system administration, managing …","tags":null,"title":"Introduction"}]