Well-known · Cross-platform

68 DHCP / BOOTP client

TCP Assigned
UDP Yes
SCTP
DCCP

What it is

DHCP client receives offers/acks on UDP/68.

When / why

Client side of DHCP address assignment.

Protocol status detail

TransportStatusMeaning
TCP Assigned Assigned by IANA, but not 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

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

Browse all ports →

Firewall rules for port 68

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 udp from <source> to any port 68

Allow UDP 68 (DHCP / BOOTP client). 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="68" protocol="udp" accept'

Allow UDP 68 (DHCP / BOOTP client) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> udp dport 68 accept

Allow UDP 68 (DHCP / BOOTP client). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p udp -s <source> --dport 68 -j ACCEPT

Allow UDP 68 (DHCP / BOOTP client). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-dhcpbootpclient-68 --priority 1000 --access Allow --direction Inbound --protocol UDP --source-address-prefixes <source> --destination-port-ranges 68

Inbound rule for 68 (DHCP / BOOTP client). 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=udp,FromPort=68,ToPort=68,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound UDP 68 (DHCP / BOOTP client). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-dhcpbootpclient-68 --direction=INGRESS --action=ALLOW --rules=udp:68 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 68 (DHCP / BOOTP client). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow DHCP / BOOTP client 68/UDP" dir=in action=allow protocol=UDP localport=68 remoteip=<source>

Inbound UDP 68 (DHCP / BOOTP client). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow DHCP / BOOTP client 68/UDP" -Direction Inbound -Action Allow -Protocol UDP -LocalPort 68 -RemoteAddress <source>

Inbound UDP 68 (DHCP / BOOTP client). 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.