Registered · Cross-platform

9042 Cassandra CQL

TCP Unofficial
UDP
SCTP
DCCP

What it is

Apache Cassandra native client protocol.

When / why

Wide-column database clients.

Protocol status detail

TransportStatusMeaning
TCP Unofficial Not assigned by IANA, but standardized, specified, or widely used on this port.
UDP Not applicable for this transport.
SCTP Not applicable for this transport.
DCCP Not applicable for this transport.

Port range

Registered (1024–49151). Assigned by IANA on request; usable without elevated privileges on most systems.

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Firewall rules for port 9042

Copy-ready inbound rules for the active transports. Replace every <source> placeholder with the specific host, subnet, or CIDR that should reach this port.

ufw

sudo ufw allow proto tcp from <source> to any port 9042

Allow TCP 9042 (Cassandra CQL). Replace <source> with the network/host that should reach it.

firewalld

sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="<source>" port port="9042" protocol="tcp" accept'

Allow TCP 9042 (Cassandra CQL) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> tcp dport 9042 accept

Allow TCP 9042 (Cassandra CQL). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p tcp -s <source> --dport 9042 -j ACCEPT

Allow TCP 9042 (Cassandra CQL). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-cassandracql-9042 --priority 1000 --access Allow --direction Inbound --protocol TCP --source-address-prefixes <source> --destination-port-ranges 9042

Inbound rule for 9042 (Cassandra CQL). Set <source> to a CIDR; lower priority number = higher precedence.

AWS Security Group

aws ec2 authorize-security-group-ingress --group-id <sg-id> --ip-permissions IpProtocol=tcp,FromPort=9042,ToPort=9042,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound TCP 9042 (Cassandra CQL). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-cassandracql-9042 --direction=INGRESS --action=ALLOW --rules=tcp:9042 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 9042 (Cassandra CQL). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow Cassandra CQL 9042/TCP" dir=in action=allow protocol=TCP localport=9042 remoteip=<source>

Inbound TCP 9042 (Cassandra CQL). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow Cassandra CQL 9042/TCP" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 9042 -RemoteAddress <source>

Inbound TCP 9042 (Cassandra CQL). Replace <source> with a host or subnet.

Rules are generated only for transports marked active for this port. They default to an inbound allow with an explicit source placeholder — never any. Review direction, scope, and rule precedence before applying in production.