Setup Utilities
Type    Port Number    Protocol
Synology Assistant    9999, 9998, 9997    UDP
Backup
Type    Port Number    Protocol
Data Replicator, Data Replicator II, Data Replicator III    9999, 9998, 9997, 137, 138, 139, 445    TCP
Network Backup and Remote Time Backup    873 (Data - Share), 3260 (iSCSI LUN), 6281 (Data - Volume)    TCP
Encrypted Network Backup and Encrypted Remote Time Backup    22    TCP
Download
Type    Port Number    Protocol
eMule
4662 (TCP), 4672 (UDP)    TCP/UDP
BT
6890 ~ 6999 (for models with firmware earlier than v2.0.1-3.0401);
16881 (for models with DSM v2.0.1 and onward)    TCP/UDP
Web Applications
Type    Port Number    Protocol
DSM    5000 (HTTP), 5001 (HTTPS)    TCP
File Station    5000 (HTTP, additional port can be added), 5001 (HTTPS, additional port can be added)    TCP
Mail Server
Type    Port Number    Protocol
SMTP    25    TCP
POP3    110    TCP
IMAP    143    TCP
IMAP over SSL/TLS    993    TCP
POP3 over SSL/TLS    995    TCP
File Transferring
Type    Port Number    Protocol
FTP, FTP over SSL, FTP over TLS    21 (command), 20 (Data connection in Active Mode), 1025-65535 (Data connection in Passive Mode; however, the default range varies with models)    TCP
AFP    548    TCP
CIFS    smbd: 139 (netbios-ssn), 445 (microsoft-ds)    TCP/UDP
Nmbd: 137, 138    UDP
NFS    111, 892, 2049    TCP/UDP
WebDAV, CalDAV    5005, 5006 (HTTPS)    TCP
iSCSI    3260    TCP
TFTP    69    UDP
Packages
Type    Port Number    Protocol
Download Station    5000    TCP
Photo Station, Web Station    80 (additional port can be added), 443 (HTTPS)    TCP
Mail Station    80 (HTTP), 443 (HTTPS)    TCP
Audio Station    1900 (UDP), 5000 (HTTP, additional port can be added), 5001 (HTTPS, additional port can be added), 5353 (Bonjour Service), 6001-6010 (AirPlay control/timing)    TCP/UDP
Surveillance Station    9900 (HTTP), 9901 (HTTPS)    TCP
Media Server    1900 (UPnP), 50001 (Content browsing), 50002 (Content streaming)    TCP/UDP
Video Station    1900 (UDP), 5000 (HTTP), 5001 (HTTPS), 9025-9040,
5002, 5004, 65001 (for using the HDHomeRun network tuner)    TCP/UDP
Note Station    5000 (HTTP), 5001 (HTTPS)    TCP
Cloud Station    6690    TCP
VPN Server (OpenVPN)    1194    UDP
VPN Server (PPTP)    1723    TCP
VPN Server (L2TP/IPSec)    500, 1701, 4500    UDP
Syslog Server    514 (additional port can be added)    TCP/UDP
iTunes Server    3689    TCP
Logitech® Media Server    3483, 9002    TCP
Directory Server    389 (LDAP), 636 (LDAP with SSL)    TCP
DHCP Server    67, 68    UDP
Central Management System (CMS)    5000 (HTTP), 5001 (HTTPS)    TCP
CIFS Scale-out Cluster   
49152-49252
TCP only: 17909, 17913, 19998, 24007, 24008, 24009-24045, 38465-38501, 4379
TCP/UDP
Proxy Server    3128    TCP
CardDAV    8008 (HTTP), 8443 (HTTPS)    TCP
Mobile Applications
Type    Port Number    Protocol
DS photo    80, 443 (HTTPS)    TCP
DS audio    5000, 5001 (HTTPS)    TCP
DS cam    5000, 5001 (HTTPS)    TCP
DS file   
Android devices:
- DS file 4.x and a DiskStation running DSM 4.3 and later: 5000, 5001 (HTTPS)
- DS file version prior to 4.0 or a DiskStation running DSM 4.2 or earlier: 5005, 5006 (HTTPS)
TCP
iOS devices:
- DS file 5.x and a DiskStation running DSM 4.3 and later: 5000, 5001 (HTTPS)
- DS file version prior to 4.0 or a DiskStation running DSM 4.2 or earlier: 5005, 5006 (HTTPS)
Windows Phone: 5000, 5001 (HTTPS)
DS finder    5000 (HTTP), 5001 (HTTPS)    TCP
DS video    5000 (HTTP), 5001 (HTTPS)    TCP
DS download    5000 (HTTP), 5001 (HTTPS)    TCP
DS cloud    6690    TCP
DS note    5000 (HTTP), 5001 (HTTPS)    TCP
Printers, UPS and Peripheral Equipments
Type    Port Number    Protocol
LPR    515    UDP
Network Printer (IPP)/CUPS    631    TCP
Bonjour    5353    UDP
Network MFP    3240-3259    TCP
UPS    3493    TCP
System
Type    Port Number    Protocol
SSH/SFTP    22    TCP
Telnet    23    TCP
Resource Monitor/SNMP    161    TCP/UDP
MySQL    3306    TCP
LDAP    389, 636 (SLAPD)    TCP