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Port 9955 (alljoyn-stm, alljoyn-mcm)

IANA assigns port 9955 to alljoyn-stm, alljoyn-mcm: Contact Port for AllJoyn standard messaging.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
alljoyn-stm TCP Contact Port for AllJoyn standard messaging Qualcomm Innovation Center -
alljoyn-mcm UDP Contact Port for AllJoyn multiplexed constrained messaging Qualcomm Innovation Center -

Registry dates for this port: registered 2012-03-14.

Check what is listening on port 9955

Linux: is anything listening on TCP 9955?
sudo ss -tlnp 'sport = :9955'
Linux: UDP 9955
sudo ss -ulnp 'sport = :9955'
Linux / macOS: which process owns the port
sudo lsof -nP -i :9955
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':9955 '
Windows (Command Prompt)
netstat -ano | findstr :9955
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 9955 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 9955
From Windows
Test-NetConnection HOST -Port 9955
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 9955

Block port 9955 in the firewall

ufw
sudo ufw deny 9955/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 9955 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 9955 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 9955' -Direction Inbound -Protocol TCP -LocalPort 9955 -Action Block
ufw
sudo ufw deny 9955/udp
iptables
sudo iptables -A INPUT -p udp --dport 9955 -j DROP
nftables
sudo nft add rule inet filter input udp dport 9955 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 9955' -Direction Inbound -Protocol UDP -LocalPort 9955 -Action Block

Related ports

9953acis9954hinp9956alljoyn9966odnsp

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