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Port 5583 (tmo-icon-sync)

IANA assigns port 5583 to tmo-icon-sync: T-Mobile SMS Protocol Message 2.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
tmo-icon-sync TCP T-Mobile SMS Protocol Message 2 Donghwan Lim -
tmo-icon-sync UDP T-Mobile SMS Protocol Message 2 Donghwan Lim -

Registry dates for this port: registered 2008-01-22.

Check what is listening on port 5583

Linux: is anything listening on TCP 5583?
sudo ss -tlnp 'sport = :5583'
Linux: UDP 5583
sudo ss -ulnp 'sport = :5583'
Linux / macOS: which process owns the port
sudo lsof -nP -i :5583
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':5583 '
Windows (Command Prompt)
netstat -ano | findstr :5583
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 5583 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 5583
From Windows
Test-NetConnection HOST -Port 5583
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 5583

Block port 5583 in the firewall

ufw
sudo ufw deny 5583/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 5583 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 5583 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 5583' -Direction Inbound -Protocol TCP -LocalPort 5583 -Action Block
ufw
sudo ufw deny 5583/udp
iptables
sudo iptables -A INPUT -p udp --dport 5583 -j DROP
nftables
sudo nft add rule inet filter input udp dport 5583 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 5583' -Direction Inbound -Protocol UDP -LocalPort 5583 -Action Block

Related ports

5581tmosms15582fac-restore5584bis-web5585bis-sync

All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.