Registered · Cross-platform

3868 Diameter

TCP Yes
UDP Yes
SCTP
DCCP

What it is

Diameter AAA protocol (RADIUS successor).

When / why

Telecom/IMS authentication and policy.

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.

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 3868

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 3868

Allow TCP 3868 (Diameter). Replace <source> with the network/host that should reach it.

sudo ufw allow proto udp from <source> to any port 3868

Allow UDP 3868 (Diameter). 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="3868" protocol="tcp" accept'

Allow TCP 3868 (Diameter) from <source>. Run 'firewall-cmd --reload' afterwards.

sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="<source>" port port="3868" protocol="udp" accept'

Allow UDP 3868 (Diameter) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> tcp dport 3868 accept

Allow TCP 3868 (Diameter). Assumes table 'inet filter' with an 'input' chain.

nft add rule inet filter input ip saddr <source> udp dport 3868 accept

Allow UDP 3868 (Diameter). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p tcp -s <source> --dport 3868 -j ACCEPT

Allow TCP 3868 (Diameter). Persist with iptables-save/netfilter-persistent.

sudo iptables -A INPUT -p udp -s <source> --dport 3868 -j ACCEPT

Allow UDP 3868 (Diameter). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-diameter-3868 --priority 1000 --access Allow --direction Inbound --protocol "*" --source-address-prefixes <source> --destination-port-ranges 3868

Inbound rule for 3868 (Diameter). 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=3868,ToPort=3868,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound TCP 3868 (Diameter). 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=3868,ToPort=3868,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound UDP 3868 (Diameter). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-diameter-3868 --direction=INGRESS --action=ALLOW --rules=tcp:3868,udp:3868 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 3868 (Diameter). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow Diameter 3868/TCP" dir=in action=allow protocol=TCP localport=3868 remoteip=<source>

Inbound TCP 3868 (Diameter). Set remoteip to a host/subnet; 'any' is discouraged.

netsh advfirewall firewall add rule name="Allow Diameter 3868/UDP" dir=in action=allow protocol=UDP localport=3868 remoteip=<source>

Inbound UDP 3868 (Diameter). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow Diameter 3868/TCP" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 3868 -RemoteAddress <source>

Inbound TCP 3868 (Diameter). Replace <source> with a host or subnet.

New-NetFirewallRule -DisplayName "Allow Diameter 3868/UDP" -Direction Inbound -Action Allow -Protocol UDP -LocalPort 3868 -RemoteAddress <source>

Inbound UDP 3868 (Diameter). 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.