sysop@hub:~/start-here$
start-here
admin_hub is a workbench for people who run IT, from the helpdesk to the server room: Windows and Linux, networks and storage, Microsoft 365 and security. Pick the line that sounds like you.
I am the helpdesk, or all of IT
The requests that fill the day, and how to get through them quickly.
helpdesk-top-ticketsThe 20 requests everyone gets: what to ask, what fixes it, when to escalate.diagnoseWizards for no network, no Wi-Fi, no printing, no sign-in.windows-pc-slow"My computer is slow" in eight steps.stop-code-lookupThe blue screen code in plain words.printer-troubleshootingQueue, spooler, drivers, and the error codes after Windows updates.windows-troubleshootingThe commands for a Windows client that misbehaves.macos-adminA Mac landed on your desk: the terminal commands that matter.onboarding-offboardingNew starters and leavers as a routine, not an emergency.new-pc-setupFrom the box to the desk, nothing forgotten.mobile-devicePhones from hand-out to wipe, without bricking one.monitor-no-pictureBlack screen, flicker, second monitor.dock-not-workingUSB-C and Thunderbolt docks.device-managementWhat MDM is, in plain words.mail-header-readerWhy was the mail late or in junk?packet-journeyTell DNS from firewall from a dead server, by the symptoms.
I run Linux servers
From "it is slow" to the service that will not start.
linux-server-slowLoad, CPU, memory, disk, network, application: in that order.log-readerDrop auth.log, syslog or the web server log and get the short version.systemd-journalctlWhy a service failed, logs by time, timers instead of cron.linux-users-permissionsAccounts, sudo, chmod, ACLs and why access is denied.linux-disks-lvmWhat fills the disk, and how to grow a volume.nginx-apacheVirtual hosts, reverse proxy, HTTPS, and what 502 means.sshKeys, tunnels, jump hosts and a hardened sshd.certificate-decoderPaste a certificate chain and see why a client refuses it.server-hardeningWhat to switch off and lock down on a new server.config-reviewerA second pair of eyes for sshd_config, nginx and Compose files.docker-container-troubleshootingEight steps for a container that does not work.cron-builderCron in plain words, and as a systemd timer.linux-playgroundPractise on a broken server, in the browser.systemd-unit-builderTurn a program into a service.disk-fullNo space left on device.regex-testerPatterns, explained part by part.
I look after the network
Plan it, cable it, and find out why it does not work.
small-office-blueprintThe whole office: layout, what to buy, checklist.ip-plan-builderVLANs and subnets with gateway, DHCP range and switch configuration.subnet-calculatorOne network in detail, with a visual map.firewall-rule-reviewerWhat the rules really leave open.switching-vlanFind a device by MAC, trunks, err-disabled ports, PoE.dns-dhcpNo address, wrong address, name does not resolve.wireguardFrom key to tunnel, and why there is no handshake.openvpnThe inherited VPN: log, certificates, the usual errors.diagnose: wi-fiSlow or dropping wireless, narrowed down in four questions.poe-budget-calculatorCan the switch power everything?snmp-monitoringAsk switches, printers and UPS units how they are.network-hardwareLights, cables, plugs, fibre and access points, with drawings.voip-sip-troubleshootingOne-way audio, dropped calls, and the router setting behind them.wifi-channel-plannerWhich access point gets which channel.dns-not-resolvingIt is always DNS, in eight steps.network-diagram-builderDraw the network and save it.dhcp-not-workingNo address or the wrong one, in nine steps.subnet-vlan-posterThe table to pin up.call-qualityChoppy calls, in seven steps.packet-journeyWhat happens between Enter and the page: start here.switch-port-finderWhich port is it on?
I keep the data alive
Disks, virtual machines and the backup that has to work on the worst day.
backup-plannerRetention, storage needed, and the gaps in your plan.snapshot-is-not-a-backupEight bad days, and which protection survives each.smart-readerPaste smartctl output: failing disk or bad cable?raid-calculatorUsable space, what may fail, and the rebuild risk.zfs-nasPool health, replacing a disk, snapshots, replication.proxmoxVMs and containers, vzdump, cluster and quorum.hyper-vCheckpoints, virtual disks, a VM that hangs in Stopping.vmware-esxiHost shell and PowerCLI, forgotten snapshots, esxtop.backup-disaster-recoveryThe checklist for the day the restore is real.storage-upgrade-plannerWhich SSD, and how to move over.file-server-migrationMove a file server without losing permissions.
I automate things
The command you half remember, and scripts that survive real use.
bash-powershell-side-by-side105 everyday tasks in both, searchable from either side.command-builderrobocopy, rsync, tar and find with every switch explained.bash-scriptingA safe skeleton, loops over odd file names, traps and locks.powershell-scriptingParameters, error handling, objects, REST, remoting.python-for-adminsStandard library first: files, CSV, HTTP, many hosts at once.regex-patternsPatterns to copy for addresses, dates and log lines.gitEnough Git to keep scripts and configuration under version control.ansibleDescribe the state, run it against many hosts.git-fix-itUndo things in Git without making it worse.powershell-playgroundObjects, filters, sorting, export: twelve missions.regex-testerPatterns, explained part by part.
I have a screwdriver in my hand
PCs, notebooks and servers from the inside, with drawings.
connector-identifierWhat is this plug, and what fits where.pc-does-not-startSeven questions to the part that stops it.desktop-pcMemory slots, front panel, paste, airflow, power supply.notebookOpening, power drain, chargers, batteries, ribbon cables, spills.serverRemote management, lights, disks, memory, power, racks.smart-readerIs this disk dying?stop-code-lookupThe blue screen code in plain words.raid-calculatorCapacity, what may fail, how long a rebuild takes.beep-code-lookupBeeps and blink codes by vendor.ups-runtime-calculatorHow long does the UPS hold?rack-plannerWhat goes where, and does it fit?bios-settings-explainedFirmware settings in plain words.buyingWhat to buy for whom, and how long to keep it.printerJams, print defects, toner, drum and fuser.disk-wipingErase drives before they leave the building.pc-build-checkerDoes the parts list fit together?asset-inventoryWhat you own, and when its warranty ends.storage-upgrade-plannerWhich SSD, and how to move over.toolkitWhat belongs in the bag.
I inherited a database
Enough SQL to ask it questions, and what to check before it becomes your problem.
sql-playground22 lessons with a practice database, in the browser.sql-basicsEvery pattern from the lessons on one page, with the dialect differences.database-backup-restoreFirst question on day one: is there a backup, and does it restore?postgresql-adminSessions, locks, sizes, vacuum, pg_dump.mysql-mariadb-adminGrants, process list, slow query log, mysqldump.sql-server-adminBlocking, backups, the log file that fills the disk.database-slowEight steps from "it is slow" to the cause.connection-string-builderEvery common form from one set of fields.sql-window-functionsRunning totals, ranks, top N per group.
I have an hour to audit a tenant
Six tools that turn exports into findings, and one page that keeps the results. Start with the export script: it produces the files most of them need.
export-scriptGet the export files with one read-only script.domain-checkCan someone send mail as your domain?ca-analyzerWhat do the access policies really enforce?app-auditWhich apps could take over the tenant?signin-analyzerIs someone already in?intune-analyzerHow healthy is the device fleet?license-optimizerWhich licences pay for nothing?attack-mapWhich attack routes stay open, and what to fix first?cockpitAll results on one page, kept in your browser.
I just took over an environment
You did not build it and nobody wrote much down. Get safe access, find out what exists, then find the biggest risks.
new-admin-first-30-daysThe first month, week by week.m365-securityIs the tenant hardened at all?backup-disaster-recoveryWhat does the backup really cover?product-lifecycleWhich systems are out of support?patch-tuesdayWhen is the next patch day, and how to roll out?onboarding-offboardingA process for people coming and going.glossaryThe terms your predecessor used.network-diagram-builderNo diagram exists? Draw it as you find things.asset-inventoryStart the list on day one.tenant-audit-one-hourThe Microsoft 365 side, in sixty minutes.
I am a Microsoft 365 admin
The daily companions for Entra ID, Exchange, Teams and licences.
aadsts-lookupWhat does this sign-in error mean?mailflow-debuggerWhy did this mail bounce?exchange-onlineDelegation, mail flow rules, message trace, audit.graphGraph PowerShell for users, licences and sign-ins.entra-pimWho holds which role, standing or eligible?entra-id-rolesWhat can each admin role really do?conditional-access-simulatorTry a policy before it locks someone out.license-comparisonWhat is included in which plan?script-generatorOffboarding, bulk users, mailbox permissions as a script.tenant-audit-one-hourA tenant you took over, reviewed in sixty minutes.
I work with Active Directory and Windows
Domain controllers, clients, policies and the classic command line.
active-directoryLockouts, replication, stale accounts, risky settings.powershellEveryday PowerShell for AD and Windows.event-idWhat does this event ID mean?group-policyList, report and back up GPOs.windows-updateWhy does this device not get updates?bitlockerRecovery keys and suspend before firmware updates.windows-lapsLocal admin passwords, read and rotated.windows-troubleshootingsfc, DISM, gpresult and network resets.kerberosHow tickets work, and how they are abused.ntfs-share-permissionsWho has access, and how to fix it with icacls.dcdiag-readerdcdiag and repadmin output in plain words.group-policy-not-applyingFrom gpresult to SYSVOL in eight steps.file-server-migrationMove a file server without losing permissions.powershell-playgroundLearn the pipeline on a pretend server.
I focus on security
How the attacks work, how to find them and what to do when one lands.
incident-simPractise an incident before you have one.aitm-phishingHow a phishing proxy gets past MFA.device-code-phishingHow tokens are stolen on the real Microsoft page.phish-analyzerIs this mail real? Drop the .eml.kqlHunting queries for Sentinel and Log Analytics.defender-xdr-huntingAdvanced hunting in Defender XDR.compromised-account-responseAn account is compromised. What now, in order.entra-id-hardeningClose the common identity gaps.exploited-nowWhat is being exploited right now.dmarc-report-readerWho sends mail in your name?incident-plan-builderOne page for the wall, before you need it.security-postersTen posters for the office wall.monitoring-baselineWhat to watch, and when to alert.password-manager-rolloutIntroduce a password manager so that it sticks.phishing-drill-kitA phishing exercise that keeps the trust.mail-header-readerIs this mail really from them?incident-simPlay through four incidents before the real one.
I manage Azure and infrastructure
Cloud resources, infrastructure as code, servers and containers.
azure-cliSubscriptions, VMs, roles and networking.bicep-armDeployments, what-if, modules and loops.terraformAzure resources as code.azure-limitsThe default quotas you will hit.server-hardeningBase system, accounts, logging, exposure.linuxAdmin and security commands.sshKeys, forwards, jump hosts, hardening.dockerContainers, images, logs and cleanup.subnet-calculatorCIDR in, network and host range out.
or do not pick at all
Three ways to find anything without knowing where it lives.
Search
Press Ctrl K anywhere. It searches every page, every snippet and every glossary term.
Paste
Paste an error code, an IP address, a domain, a JWT or a timestamp into the search and get an answer on the spot.
Browse
Tools, cheat sheets, checklists, explainers and the glossary are each one sorted list with a filter.