Port 993: IMAPS
Mailbox access over TLS. The normal port for mail apps to read mail.
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Port Lookup
Port 993 at a glance
Port993
ProtocolTCP
ServiceIMAPS
Open to the Internet?Yes, if you run this service publicly
See What Is Listeningss -lntup | grep ':993 '
Test From Outsidenc -zv your-server 993
Block with UFWufw deny 993/tcp
Block with nftablesnft add rule inet filter input tcp dport 993 drop
IMAPS uses TCP port 993. Mailbox access over TLS.
The normal port for mail apps to read mail.
Open port 993 only on servers that run IMAPS, and keep the software patched: public services are scanned within minutes of going online.
Other Ports
20 FTP Data21 FTP22 SSH23 Telnet25 SMTP53 DNS67 DHCP Server80 HTTP110 POP3123 NTP143 IMAP161 SNMP389 LDAP443 HTTPS445 SMB465 SMTPS514 Syslog587 Mail Submission853 DNS over TLS993 IMAPS995 POP3S1194 OpenVPN1433 Microsoft SQL Server1900 SSDP / UPnP2049 NFS2083 cPanel (SSL)2087 WHM (SSL)3306 MySQL / MariaDB3389 RDP3478 STUN / TURN5060 SIP5432 PostgreSQL5900 VNC6379 Redis8006 Proxmox VE8080 HTTP Alternate8443 HTTPS Alternate11211 Memcached25565 Minecraft27017 MongoDB51820 WireGuard
Questions
What is port 993 used for?
IMAPS. Mailbox access over TLS.
Is it safe to open port 993?
Yes, if you run this service publicly. The normal port for mail apps to read mail.
How do I check if port 993 is open?
On the server, ss -lntup | grep ':993 ' shows what is listening. From another machine, nc -zv your-server 993 shows whether the firewall lets it through.
How do I block port 993?
With UFW: ufw deny 993/tcp. With nftables, add a drop rule for dport 993 in your input chain.
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