Registered · Cross-platform

6690 Synology Cloud Station

TCP Unofficial
UDP
SCTP
DCCP

What it is

Synology file sync.

When / why

NAS file synchronization.

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 6690

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 6690

Allow TCP 6690 (Synology Cloud Station). 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="6690" protocol="tcp" accept'

Allow TCP 6690 (Synology Cloud Station) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> tcp dport 6690 accept

Allow TCP 6690 (Synology Cloud Station). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p tcp -s <source> --dport 6690 -j ACCEPT

Allow TCP 6690 (Synology Cloud Station). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-synologycloudstation-6690 --priority 1000 --access Allow --direction Inbound --protocol TCP --source-address-prefixes <source> --destination-port-ranges 6690

Inbound rule for 6690 (Synology Cloud Station). 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=6690,ToPort=6690,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound TCP 6690 (Synology Cloud Station). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-synologycloudstation-6690 --direction=INGRESS --action=ALLOW --rules=tcp:6690 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 6690 (Synology Cloud Station). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow Synology Cloud Station 6690/TCP" dir=in action=allow protocol=TCP localport=6690 remoteip=<source>

Inbound TCP 6690 (Synology Cloud Station). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow Synology Cloud Station 6690/TCP" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 6690 -RemoteAddress <source>

Inbound TCP 6690 (Synology Cloud Station). 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.