Port 3538 (ibm-diradm)

IANA assigns port 3538 to ibm-diradm: IBM Directory Server.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference

ibm-diradm TCP IBM Directory Server - -

ibm-diradm UDP IBM Directory Server - -

Linux: is anything listening on TCP 3538?

sudo ss -tlnp 'sport = :3538'

Linux: UDP 3538

sudo ss -ulnp 'sport = :3538'

Linux / macOS: which process owns the port

sudo lsof -nP -i :3538

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':3538 '

Windows (Command Prompt)

netstat -ano | findstr :3538

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 3538 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 3538

From Windows

Test-NetConnection HOST -Port 3538

UDP probe (no reply does not prove it is closed)

nc -vzu -w 5 HOST 3538

ufw

sudo ufw deny 3538/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 3538 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 3538 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 3538' -Direction Inbound -Protocol TCP -LocalPort 3538 -Action Block

ufw

sudo ufw deny 3538/udp

iptables

sudo iptables -A INPUT -p udp --dport 3538 -j DROP

nftables

sudo nft add rule inet filter input udp dport 3538 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block UDP 3538' -Direction Inbound -Protocol UDP -LocalPort 3538 -Action Block

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