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Port 1881 (ibm-mqseries2)

IANA assigns port 1881 to ibm-mqseries2: IBM WebSphere MQ Everyplace.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
ibm-mqseries2 TCP IBM WebSphere MQ Everyplace Jane Porter -
ibm-mqseries2 UDP IBM WebSphere MQ Everyplace Jane Porter -

Check what is listening on port 1881

Linux: is anything listening on TCP 1881?
sudo ss -tlnp 'sport = :1881'
Linux: UDP 1881
sudo ss -ulnp 'sport = :1881'
Linux / macOS: which process owns the port
sudo lsof -nP -i :1881
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':1881 '
Windows (Command Prompt)
netstat -ano | findstr :1881
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 1881 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 1881
From Windows
Test-NetConnection HOST -Port 1881
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 1881

Block port 1881 in the firewall

ufw
sudo ufw deny 1881/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 1881 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 1881 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 1881' -Direction Inbound -Protocol TCP -LocalPort 1881 -Action Block
ufw
sudo ufw deny 1881/udp
iptables
sudo iptables -A INPUT -p udp --dport 1881 -j DROP
nftables
sudo nft add rule inet filter input udp dport 1881 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 1881' -Direction Inbound -Protocol UDP -LocalPort 1881 -Action Block

Related ports

1879nettgain-nms1880vsat-control1882ecsqdmn1883MQTT

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.