Well-known · Cross-platform

990 FTPS control

TCP Yes
UDP Yes
SCTP —
DCCP —

What it is

FTP control channel over implicit TLS/SSL.

When / why

Implicit FTPS control.

Protocol status detail

TransportStatusMeaning
TCP Yes Assigned by IANA and standardized, specified, or widely used on this port.
UDP Yes Assigned by IANA and standardized, specified, or widely used on this port.
SCTP — Not applicable for this transport.
DCCP — Not applicable for this transport.
« 989 FTPS data 991 NAS »

Port range

Well-known (0–1023). System port for a core service. On Unix-like systems, binding it requires superuser privileges.

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Firewall rules for port 990

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 990

Allow TCP 990 (FTPS control). Replace <source> with the network/host that should reach it.

sudo ufw allow proto udp from <source> to any port 990

Allow UDP 990 (FTPS control). 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="990" protocol="tcp" accept'

Allow TCP 990 (FTPS control) from <source>. Run 'firewall-cmd --reload' afterwards.

sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="<source>" port port="990" protocol="udp" accept'

Allow UDP 990 (FTPS control) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> tcp dport 990 accept

Allow TCP 990 (FTPS control). Assumes table 'inet filter' with an 'input' chain.

nft add rule inet filter input ip saddr <source> udp dport 990 accept

Allow UDP 990 (FTPS control). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p tcp -s <source> --dport 990 -j ACCEPT

Allow TCP 990 (FTPS control). Persist with iptables-save/netfilter-persistent.

sudo iptables -A INPUT -p udp -s <source> --dport 990 -j ACCEPT

Allow UDP 990 (FTPS control). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-ftpscontrol-990 --priority 1000 --access Allow --direction Inbound --protocol "*" --source-address-prefixes <source> --destination-port-ranges 990

Inbound rule for 990 (FTPS control). 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=990,ToPort=990,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound TCP 990 (FTPS control). Replace <source-cidr> (e.g. 10.0.0.0/16).

aws ec2 authorize-security-group-ingress --group-id <sg-id> --ip-permissions IpProtocol=udp,FromPort=990,ToPort=990,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound UDP 990 (FTPS control). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-ftpscontrol-990 --direction=INGRESS --action=ALLOW --rules=tcp:990,udp:990 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 990 (FTPS control). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow FTPS control 990/TCP" dir=in action=allow protocol=TCP localport=990 remoteip=<source>

Inbound TCP 990 (FTPS control). Set remoteip to a host/subnet; 'any' is discouraged.

netsh advfirewall firewall add rule name="Allow FTPS control 990/UDP" dir=in action=allow protocol=UDP localport=990 remoteip=<source>

Inbound UDP 990 (FTPS control). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow FTPS control 990/TCP" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 990 -RemoteAddress <source>

Inbound TCP 990 (FTPS control). Replace <source> with a host or subnet.

New-NetFirewallRule -DisplayName "Allow FTPS control 990/UDP" -Direction Inbound -Action Allow -Protocol UDP -LocalPort 990 -RemoteAddress <source>

Inbound UDP 990 (FTPS control). 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.