- Require TLS and authenticated submission.
- Make sure the server is not an open relay.
- Publish SPF, DKIM and DMARC for the domain.
Port 3264: cc:mail/lotus
Port 3264 is assigned by IANA to ccmail (cc:mail/lotus).
3264
How ccmail works
EmailMail servers hand messages to each other over port 3264, one hop at a time, until the recipient's server.
- Transport
- TCP · UDP
- Exposure risk
- not rated depends on the program listening
- Encryption
- Unknownnot stated by the registry
- IANA status
- Assigned1 registered service
- Range
- Registered (1024-49151)
- Category
Is port 3264 dangerous?
We have no specific security note for port 3264. Its risk depends on the program actually listening on it. General advice for email services:
IANA registry entries for port 3264
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| ccmail | 3264 | TCP, UDP | cc:mail/lotus | - | - |
// source: IANA service name and port number registry
Which program uses port 3264, and is it reachable?
Linux
sudo ss -ltnup 'sport = :3264' # process listening on 3264
sudo lsof -nP -i :3264macOS
sudo lsof -nP -i :3264
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3264 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 3264 netstat -ano | findstr :3264
From another machine
nmap -p 3264 -sV <host> sudo nmap -sU -p 3264 <host> nc -zv <host> 3264
Block it in the firewall
sudo ufw deny 3264/tcp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 3264" -Direction Inbound -LocalPort 3264 -Protocol TCP -Action Block # Windows
What is port 3264 used for?
Port 3264 is assigned by IANA to ccmail (cc:mail/lotus).
Is port 3264 TCP or UDP?
Port 3264 is registered for TCP and UDP.
Is it safe to open port 3264?
It depends on the program that listens on it. Open it only for a service you know and only to the networks that need it. Require TLS and authenticated submission.
How do I check if port 3264 is open?
On Linux run "ss -ltnup 'sport = :3264'", on macOS "lsof -nP -i :3264", and on Windows "netstat -ano | findstr :3264" to see the local process. From another machine, "nmap -p 3264 <host>" shows whether it is reachable.