Mobile devices: Exchange ActiveSync and device management

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grommunio serves phones and tablets over Exchange ActiveSync (EAS), implemented by grommunio-sync. Device management in grommunio covers the ActiveSync relationship between a mailbox and a device: listing devices, checking their sync status, forcing a full resync, removing stale server-side state, enforcing sync policies (PIN, lock timeout, encryption) and issuing a remote wipe.

It is not a unified endpoint management (UEM) product. grommunio does not install apps, distribute certificates or configure device settings outside the EAS policy set, and every policy is only as effective as the client's implementation of it.

This guide takes you from a working grommunio installation to a user whose device synchronises mail, calendar, contacts and tasks, and shows where devices are reviewed and managed: in grommunio Web, in the Admin UI and on the command line.

How it fits together

Component	Role for EAS
nginx	Terminates TLS on port 443 and passes `/Microsoft-Server-ActiveSync` to the grommunio-sync PHP-FPM pool (location shipped in `/usr/share/grommunio-common/nginx/locations.d/grommunio-sync.conf`)
grommunio-sync (PHP-FPM pool `grommunio-sync-pool`, socket `/run/php-fpm/php-grommunio-sync-fpm.sock`)	Implements EAS 2.5 to 16.1: provisioning, folder hierarchy sync, item sync, push (Ping), policies, wipe handshake
gromox-zcore	php-mapi transport; grommunio-sync reads and writes the mailbox through zcore
gromox-http	Information store (exmdb) behind zcore; also answers AutoDiscover at `/Autodiscover/Autodiscover.xml`
Redis	Transient state of running sync threads; feeds `grommunio-sync-top`, the Admin UI Mobile devices view and the "last connect" timestamps
grommunio-admin-api	Serves the effective sync policy and the wipe status of a device to grommunio-sync; keeps wipe requests in its database
User store	Persistent per-device sync state in the hidden `GS-SyncState` folder, outside `IPM_SUBTREE`

A device session runs as follows:

The device locates the server via AutoDiscover (or you enter the server name manually) and sends requests to https://mail.example.com/Microsoft-Server-ActiveSync.
nginx forwards the request to grommunio-sync, which authenticates the user through php-mapi against gromox-zcore. Users without the EAS privilege are rejected.
On the first contact the device is provisioned: grommunio-sync fetches the effective sync policy for the user from the Admin API and the device acknowledges it (PIN, lock timeout and so on).
The device runs FolderSync and Sync; grommunio-sync records the per-device state in the user's store. Between changes the device sits in a Ping request, which is how push mail works.

Because the device state lives inside the mailbox, it travels with the mailbox during backups, migrations and homeserver moves, and it is deleted with the mailbox. Redis holds only what is needed to display live connections.

Prerequisites

A grommunio installation with working DNS and TLS, for example after the post-installation guide.
DNS: mail.example.com resolves from every network your devices use, and autodiscover.example.com points to the same host (A/AAAA or CNAME). Alternatively publish an SRV record _autodiscover._tcp.example.com. See autodiscover(7).
A publicly trusted TLS certificate covering both names. Mobile operating systems refuse untrusted certificates or require manual trust profiles; expired certificates stop synchronisation on every device at once.
TCP port 443 reachable from the mobile networks. EAS needs no other port.
Running services: nginx, php-fpm, gromox-http, gromox-zcore, Redis and grommunio-admin-api.
A user with a mailbox and, for the first test, a device you can afford to reset. Policies apply during the first sync and a wipe test is destructive.

1. Check the server side

Confirm the host name, the installed components and the services before touching a device.

hostname -f
rpm -q grommunio-sync gromox grommunio-admin-api
systemctl is-active nginx php-fpm gromox-http gromox-zcore redis@grommunio grommunio-admin-api

Every service should report active. Then probe the two HTTPS endpoints from outside the server, without disabling certificate verification. If curl rejects the certificate, mobile devices will reject it too.

curl -sS -o /dev/null -w '%{http_code}\n' https://mail.example.com/Microsoft-Server-ActiveSync
curl -sS -o /dev/null -w '%{http_code}\n' https://autodiscover.example.com/Autodiscover/Autodiscover.xml

Expected result: 401 for both URLs. An unauthenticated request is answered with an authentication challenge, which proves that nginx, the PHP-FPM pool and gromox-http are wired up. A 404, 502 or 503 points at the nginx configuration, a stopped php-fpm or a stopped gromox-http.

To test AutoDiscover the way an EAS client does, use gromox-dscli(8) with the --eas request schema:

PASS='<strong-password>' gromox-dscli --eas -e [email protected]

Expected result: an XML response that names the server. With -v, the request and the raw response are printed for inspection.

2. Enable EAS for the user

ActiveSync access is a per-user privilege. Without it, the user cannot log in at the EAS endpoint even with a correct password.

Admin UI: open Domains, select the domain, open Users, click the user, and on the Account tab enable Allow EAS. Click Save at the bottom of the page. To pre-fill the privilege for newly created users, set it under Defaults (globally or per domain); see Administration.

CLI:

grommunio-admin user modify [email protected] --privEas 1
grommunio-admin user query -f [email protected] username status privEas

Expected result: the query lists the user with privEas set to 1. Boolean fields accept 0/1, yes/no and true/false. grommunio-admin user show [email protected] prints the full record. To withdraw ActiveSync access later, set --privEas 0; this blocks new logins but leaves existing device states in the store (see step 6 for cleanup).

The privilege is stored in grommunio, not in LDAP. Users imported from LDAP get it through the defaults or by setting it explicitly as shown. See grommunio-admin user for all fields.

3. Connect a device

Use the account type Microsoft Exchange (sometimes labelled Exchange ActiveSync or Exchange), never Microsoft 365 or Outlook.com, which are tied to Microsoft's cloud.

Setting	Value
E-mail address	`[email protected]`
Username	`[email protected]` (the full address; leave any Domain field empty)
Password	The user's grommunio password
Server	`mail.example.com` (manual setup only)
Encryption	SSL/TLS, port 443
Data to sync	Mail, Contacts, Calendars, Tasks/Reminders, Notes, as offered by the client

grommunio-sync expects the full e-mail address as login name (USE_FULLEMAIL_FOR_LOGIN in /etc/grommunio-sync/grommunio-sync.conf.php), which is also what AutoDiscover hands to the device.

With AutoDiscover

Enter the e-mail address and the password and let the device discover the server. The device queries autodiscover.example.com (or the SRV record) and receives the ActiveSync URL. Nothing else is required. If a client offers both a sign-in and a manual path, the sign-in path is the AutoDiscover path.

Manual server entry

When AutoDiscover is not published or the client insists on manual data, choose the manual or advanced option and enter server, username and password as in the table above. On iOS and iPadOS this is Configure Manually after entering the address; Android mail apps ask for Server and Username in their Manual setup; Outlook for iOS and Android exposes the server field under Advanced settings when the account type Exchange is chosen. Menu names vary between vendors and versions.

Shared mailboxes on a phone

grommunio-sync supports impersonation over EAS. To put a shared mailbox on a device with full rights, use the combined login <shared-mailbox>!<your-address>, for example [email protected][email protected], with Alice's own password. AutoDiscover understands this form and the server checks that Alice holds owner rights on the target store. A remote wipe issued against such a session is automatically reduced to an account-only wipe. See the release notes.

4. Prove synchronisation

On the device, the folder list appears first (FolderSync), followed by the content of the folders (Sync). Send a message to the user and create an appointment on the device; the message should arrive on the device and the appointment should show up in grommunio Web.

On the server, list the user's devices:

grommunio-admin user devices [email protected] list

Expected result: one line per device with the columns ID, Device, Agent, Version (EAS protocol version), Last connect and Status (wipe status). grommunio-admin user devices [email protected] show <DEVICE-ID> prints the details recorded by grommunio-sync, including devicetype, devicemodel, deviceos, useragent, firstsynctime, lastupdatetime, lastconnecttime, asversion and wipeStatus.

Watch live connections with the console tool shipped with grommunio-sync:

grommunio-sync-top

It shows one line per running request with PID, ADDRESS, USER, COMMAND (for example Provision, FolderSync, Sync, Ping), TIME, AGENT, DEVID, additional information and the EAS version. Type f:alice to filter on a user, l: to grep the log, t: to tail the log, e: to tail the error log, h for help and q to quit. The Admin UI offers the same view under Mobile devices, and Live Status lists every EAS request together with the other HTTP protocols.

Check the grommunio-sync logs for the user:

grep -i '[email protected]' /var/log/grommunio-sync/grommunio-sync.log | tail -n 50
tail -n 100 /var/log/grommunio-sync/grommunio-sync-error.log

Expected result: provisioning, FolderSync and Sync entries for the device ID and no entries in the error log for this session.

5. Review devices in grommunio Web and the Admin UI

grommunio Web (user self-service). Under Settings, Mobile Devices, the user sees every device paired with the mailbox: friendly name, operating system, first and last sync, device ID, and on click the synchronised folders, the grommunio-sync version, the negotiated EAS version and the provisioning policy in force. The actions Wipe Device (requires the user's password), Full Resync, Remove Device and Refresh are described in Mobile Device Management. Point users to that page and to the clean-restart procedure in the user troubleshooting page before they contact you.

Admin UI, per user. Open the user and switch to the Mobile devices tab to see the devices of this mailbox. The tab offers Remote wipe and Cancel remote wipe. The Sync policy tab next to it holds the user-specific policy (see step 7).

Admin UI, server-wide. Mobile devices in the drawer is a live table of current connections, refreshed every two seconds, with a text filter and an activity filter. It is the graphical equivalent of grommunio-sync-top. Use it to see who is syncing right now, not as an inventory: devices that are idle between Ping requests appear and disappear as their requests come and go. See Administration.

6. Manage devices from the CLI

All device operations hang off grommunio-admin user devices. USERSPEC is the user name or ID; device IDs come from list.

grommunio-admin user devices [email protected] list
grommunio-admin user devices [email protected] show <DEVICE-ID>
grommunio-admin user devices [email protected] resync <DEVICE-ID>
grommunio-admin user devices [email protected] remove <DEVICE-ID>
grommunio-admin user devices [email protected] wipe --mode account <DEVICE-ID>
grommunio-admin user devices [email protected] wipe --mode normal <DEVICE-ID>
grommunio-admin user devices [email protected] wipe --mode cancel <DEVICE-ID>

Subcommand	Effect	Takes effect
`list`	Devices of the user with EAS version, last connect time and wipe status	Immediately
`show DEVICE …`	Full device record from the sync state	Immediately
`resync [DEVICE …]`	Marks the device for a full resync: hierarchy first, then all content	On the device's next request
`remove [DEVICE …]`	Deletes the device state from the store and the device's wipe record	Immediately; a device that still has the account configured re-registers and performs a full sync
`wipe --mode MODE DEVICE`	Sets the wipe status: `normal` (whole device), `account` (this account's data only) or `cancel` (withdraw a pending request); default is `normal`	On the device's next authenticated request

list, show, resync and remove accept several device IDs; without an ID they act on all devices of the user. wipe requires exactly one device ID. Additional examples are in the CLI cookbook.

Use resync when items are missing on a device or a folder does not update. Use remove for devices that have been retired, or as part of the clean-restart procedure: remove the account from the device, remove the device state, wait a few minutes, recreate the account.

7. Sync policies

Sync policies are the EAS provisioning rules a device must accept before it may synchronise. grommunio applies them in three layers:

The server default, visible with grommunio-admin config get sync.defaultPolicy.
The domain policy: Domains, select the domain, Sync policy tab. It applies to all users of the domain.
The user policy: Users, select the user, Sync policy tab. It overrides the domain policy for this user.

In both tabs, blue controls mark values that deviate from the inherited policy; grey controls inherit. A policy change is pushed to the devices at their next contact, when grommunio-sync re-provisions them. The Admin UI exposes, among others:

Policy	Purpose
Password required	Device must have a lock PIN or password
Minimum password length	Minimum number of characters
Require alphanumeric password / Minimum password character sets	Complexity requirements
Allow simple passwords	Permit repeating or sequential PINs
Password expiration (days)	Force periodic PIN changes
Number of failed login attempts allowed	Device wipes itself after that many wrong entries (client-dependent)
Inactivity (seconds) before device locks itself	Auto-lock timeout
Require encryption on storage card	Encryption of removable storage
Device encryption, camera, storage card, Wi-Fi, Bluetooth, browser, unsigned apps, attachments and maximum attachment size, mail and calendar age filters	Feature restrictions and sync limits from the EAS policy set

A common baseline for company devices is: password required, minimum length 6, lock after 300 to 900 seconds of inactivity, 10 failed attempts, device encryption required. Everything else is client-dependent: current iOS and Android releases honour PIN, complexity, lock timeout, encryption and camera rules; many other keys date from older device generations and are silently ignored. Validate a policy with a real device of each platform you support. Test clients that only speak the protocol do not enforce anything.

Two settings in the grommunio-sync configuration file /etc/grommunio-sync/grommunio-sync.conf.php (linked as /usr/share/grommunio-sync/config.php) govern provisioning as a whole: PROVISIONING (enabled by default) switches policy enforcement on, and LOOSE_PROVISIONING (disabled by default) admits devices that cannot provision while still enforcing policies on devices that can. Leave both at their defaults unless you must support legacy clients.

8. Remote wipe

Mode	Admin UI label	Result on the device
`normal`	Wipe all data	Full device wipe, vendor-dependent; equivalent to a factory reset on most platforms
`account`	Wipe only data related to this account	Removes the grommunio account and its mail, contacts and calendar items; other data stays
`cancel`	Cancel remote wipe	Withdraws a pending request that the device has not acknowledged yet

A wipe can be requested from three places: by the user in grommunio Web (Wipe Device, password required), by an administrator in the Admin UI (Remote wipe on the user's Mobile devices tab) and on the CLI with wipe --mode. In every case the request is stored as a pending status; the device receives the command in the response to its next authenticated request, acknowledges it and executes it. list shows the current status in the Status column.

Recommended procedure for a lost or stolen device:

Identify the device with list and show: match the model, the user agent and the last connect time against what the user reports.
Choose the mode. Prefer account on personally owned devices; use normal only where company policy and the user's consent cover a full reset.
Issue the wipe and leave the account credentials valid until the device has acknowledged the request. A device that can no longer authenticate is never told to wipe.
Watch list for the status change and the grommunio-sync log for the device's acknowledgement. Devices that are switched off, offline or have already had the account removed stay in pending state indefinitely; cancel the request if the device turns up.
After the acknowledgement, remove the device state with remove, change the user's password (grommunio-admin passwd [email protected]) and, if appropriate, withdraw the EAS privilege.

Wipes issued against an impersonated shared-mailbox session are reduced to account mode by grommunio-sync, so a personal device is never reset because of a shared mailbox.

Verification checklist

Check	How	Expected result
DNS	`dig +short mail.example.com` and `dig +short autodiscover.example.com`	Both resolve to the grommunio host from the client networks
TLS	`curl -sS https://mail.example.com/` without `-k`	No certificate error; certificate covers both names
Services	`systemctl is-active nginx php-fpm gromox-http gromox-zcore redis@grommunio grommunio-admin-api`	All `active`
Endpoint	`curl -sS -o /dev/null -w '%{http_code}\n' https://mail.example.com/Microsoft-Server-ActiveSync`	`401`
AutoDiscover	`PASS='…' gromox-dscli --eas -e [email protected]`	XML response naming the server
User privilege	`grommunio-admin user query -f [email protected] privEas`	`1`
Provisioning	Add the account on a device	Device accepts the policy and, if required, asks for a PIN
Hierarchy and content	Device shows folders; a test mail and a test appointment sync both ways	Items visible on the device and in grommunio Web
Device registered	`grommunio-admin user devices [email protected] list` and grommunio Web Mobile Devices	Device listed with a recent last connect time
Live view	`grommunio-sync-top` or Admin UI Mobile devices while the device syncs	Request lines for the user appear
Resync	`resync`, then wait for the next request	Device performs a full resync; items reappear
Remove	`remove`, with the account removed from the device first	Device disappears from the list and does not return
Policy change	Change the lock timeout in the domain or user policy	Device is re-provisioned at its next contact and applies the new value
Restart	`systemctl restart php-fpm nginx`	Devices reconnect and continue syncing
Logs	`/var/log/grommunio-sync/grommunio-sync-error.log`	No errors for the tested session

Troubleshooting

Symptom	Likely cause	What to check/fix
Device cannot find the server during setup	AutoDiscover DNS missing or not published in the client's DNS view; certificate does not cover `autodiscover.example.com`	Resolve `autodiscover.example.com` from the client network; test with `gromox-dscli --eas`; enable `oxdisco_request_logging` in `/etc/gromox/gromox.cfg` temporarily; fall back to manual server entry
Device reports a certificate error	Self-signed, incomplete chain or expired certificate	`curl` without `-k` from outside; install a publicly trusted certificate with the full chain
Account setup fails with wrong credentials although the password is correct	Username not the full address, `Domain` field filled, EAS privilege not set, user suspended	Use `[email protected]` as username with an empty domain; `grommunio-admin user query -f [email protected] status privEas`; `grommunio-admin user login [email protected]` to test authentication
Endpoint always returns `401` for the device, `grommunio-sync.log` shows no login	Request never reaches PHP or authentication backend down	`systemctl status php-fpm gromox-zcore`; `/var/log/nginx/nginx-sync-error.log`; `/var/log/grommunio-sync/grommunio-sync-fpm.log`
Repeated `401`/`403` in `/var/log/nginx/nginx-sync-access.log` for one user	Stale password on a device after a password change, or privilege withdrawn	Identify the device by IP and user agent in `grommunio-sync-top`; update or remove the account on the device
Device not listed although it syncs	Looking at the wrong user or the Admin UI live view instead of the device list	`grommunio-admin user devices <user> list`; grommunio Web Mobile Devices, Refresh
Sync stuck, no new mail, last connect time old	Device offline, push (Ping) blocked by the network, client not provisioned, broken sync state	Check `Last connect` in `list`; watch `grommunio-sync-top` for Ping requests from the device; `resync`; as a last resort the clean-restart procedure (remove account, `remove`, wait, re-add)
Items missing or duplicated, flags not updating	Corrupted device state or change-number problems in the mailbox	`resync` first; if the mailbox itself shows ICS problems see `cgkreset` in gromox-mbop(8)
`resync` has no visible effect	The device has not connected since	Wait for the next request or trigger a manual sync on the device
Device reappears after `remove`	The account is still configured on the device	Remove the account on the device first, then `remove` the state
Policy not applied on the device	Device has not reconnected; client does not implement the policy key; `PROVISIONING` disabled	Force a sync on the device; test with a native mail client; confirm `PROVISIONING` in `/etc/grommunio-sync/grommunio-sync.conf.php`
Wipe stays pending	Device offline, switched off, or the account was removed before the wipe was delivered; password changed before acknowledgement	Keep credentials valid until acknowledgement; `wipe --mode cancel` if the device turns up; otherwise rely on password change and privilege removal
Shared mailbox login rejected	Impersonation form wrong or missing owner rights	Login must be `[email protected][email protected]`; grant owner permission on the shared store
`grommunio-sync-top` aborts with `Permission denied` on `config.php`	The wrapper switches to the `grosync` user, which cannot read `/etc/grommunio-sync/grommunio-sync.conf.php` (mode 640, group `grosync`)	Check `id grosync` and the file's group; use the Admin UI Mobile devices view or `grommunio-admin user devices … list` in the meantime

Operating notes

Logs. grommunio-sync writes to files, not to the journal:

File	Content
`/var/log/grommunio-sync/grommunio-sync.log`	Request log: user, device ID, command, result
`/var/log/grommunio-sync/grommunio-sync-error.log`	Errors and warnings only
`/var/log/grommunio-sync/grommunio-sync-fpm.log`	PHP-FPM output of the grommunio-sync pool
`/var/log/nginx/nginx-sync-access.log`, `/var/log/nginx/nginx-sync-error.log`	HTTP status codes and proxy errors for `/Microsoft-Server-ActiveSync` (separate from the grommunio Web logs)

The default verbosity is LOGLEVEL_INFO (LOGLEVEL in /etc/grommunio-sync/grommunio-sync.conf.php). Raise it only for the duration of an investigation; the debug and WBXML levels record message content. /etc/logrotate.d/grommunio-sync.lr rotates the files under /var/log/grommunio-sync/ once they exceed 4 MB, keeps four generations and deletes archives after a year. gromox-zcore and gromox-http log to the journal (journalctl -u gromox-zcore -u gromox-http); a general log overview is in Troubleshooting.

Monitoring. Monitor technical health rather than device inventories: HTTP reachability and the 401 challenge of the endpoint, certificate expiry, the share of 401/403 responses in /var/log/nginx/nginx-sync-access.log, growth of grommunio-sync-error.log, saturation of the PHP-FPM pool (each Ping request holds a worker) and stale Last connect times of devices that should be active. Device IDs, IMEIs and user agents are personal data; keep exports of device lists to what your policy requires.

State and backups. Device states are part of the user store and are therefore included in mailbox backups and in full exports with gromox-exm2mt -ar /; an export restricted to IPM_SUBTREE omits them. Redis contents are transient and need no backup. See Operations for the general backup procedure.

Housekeeping. Review device lists periodically and remove states of devices whose last connect time is months old. When a user leaves, withdraw the EAS privilege, wipe the account data if required, then delete the user; the states go with the mailbox.

Updates and high availability. Update grommunio-sync with zypper together with the rest of the stack and re-run the endpoint check and one device sync afterwards. Because grommunio-sync is stateless PHP behind nginx and the device state lives in the store, /Microsoft-Server-ActiveSync can be load-balanced across web nodes; the architecture and high availability pages contain the routing examples.