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Port 3863 (asap-tcp, asap-udp, asap-sctp)

IANA assigns port 3863 to asap-tcp, asap-udp, asap-sctp: asap tcp port.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
asap-tcp TCP asap tcp port - -
asap-udp UDP asap udp port - RFC 5352
asap-sctp SCTP asap sctp - RFC 5352

Check what is listening on port 3863

Linux: is anything listening on TCP 3863?
sudo ss -tlnp 'sport = :3863'
Linux: UDP 3863
sudo ss -ulnp 'sport = :3863'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3863
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3863 '
Windows (Command Prompt)
netstat -ano | findstr :3863
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3863 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3863
From Windows
Test-NetConnection HOST -Port 3863
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3863

Block port 3863 in the firewall

ufw
sudo ufw deny 3863/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3863 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3863 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3863' -Direction Inbound -Protocol TCP -LocalPort 3863 -Action Block
ufw
sudo ufw deny 3863/udp
iptables
sudo iptables -A INPUT -p udp --dport 3863 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3863 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3863' -Direction Inbound -Protocol UDP -LocalPort 3863 -Action Block

Related ports

3861winshadow-hd3862giga-pocket3864asap-tcp-tls, asap-sctp-tls3865xpl

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