Well-known · Cross-platform

749 Kerberos admin

TCP Yes
UDP Yes
SCTP —
DCCP —

What it is

Kerberos administration (kadmin).

When / why

MIT/Heimdal Kerberos realm administration.

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.
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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 749

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 749

Allow TCP 749 (Kerberos admin). Replace <source> with the network/host that should reach it.

sudo ufw allow proto udp from <source> to any port 749

Allow UDP 749 (Kerberos admin). 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="749" protocol="tcp" accept'

Allow TCP 749 (Kerberos admin) from <source>. Run 'firewall-cmd --reload' afterwards.

sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="<source>" port port="749" protocol="udp" accept'

Allow UDP 749 (Kerberos admin) from <source>. Run 'firewall-cmd --reload' afterwards.

nftables

nft add rule inet filter input ip saddr <source> tcp dport 749 accept

Allow TCP 749 (Kerberos admin). Assumes table 'inet filter' with an 'input' chain.

nft add rule inet filter input ip saddr <source> udp dport 749 accept

Allow UDP 749 (Kerberos admin). Assumes table 'inet filter' with an 'input' chain.

iptables

sudo iptables -A INPUT -p tcp -s <source> --dport 749 -j ACCEPT

Allow TCP 749 (Kerberos admin). Persist with iptables-save/netfilter-persistent.

sudo iptables -A INPUT -p udp -s <source> --dport 749 -j ACCEPT

Allow UDP 749 (Kerberos admin). Persist with iptables-save/netfilter-persistent.

Azure NSG

az network nsg rule create -g <resource-group> --nsg-name <nsg> -n Allow-kerberosadmin-749 --priority 1000 --access Allow --direction Inbound --protocol "*" --source-address-prefixes <source> --destination-port-ranges 749

Inbound rule for 749 (Kerberos admin). 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=749,ToPort=749,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound TCP 749 (Kerberos admin). 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=749,ToPort=749,IpRanges="[{CidrIp=<source-cidr>}]"

Inbound UDP 749 (Kerberos admin). Replace <source-cidr> (e.g. 10.0.0.0/16).

GCP firewall

gcloud compute firewall-rules create allow-kerberosadmin-749 --direction=INGRESS --action=ALLOW --rules=tcp:749,udp:749 --source-ranges=<source-cidr> --network=<network>

Ingress rule for 749 (Kerberos admin). Scope with --source-ranges and optionally --target-tags.

Windows netsh

netsh advfirewall firewall add rule name="Allow Kerberos admin 749/TCP" dir=in action=allow protocol=TCP localport=749 remoteip=<source>

Inbound TCP 749 (Kerberos admin). Set remoteip to a host/subnet; 'any' is discouraged.

netsh advfirewall firewall add rule name="Allow Kerberos admin 749/UDP" dir=in action=allow protocol=UDP localport=749 remoteip=<source>

Inbound UDP 749 (Kerberos admin). Set remoteip to a host/subnet; 'any' is discouraged.

Windows PowerShell

New-NetFirewallRule -DisplayName "Allow Kerberos admin 749/TCP" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 749 -RemoteAddress <source>

Inbound TCP 749 (Kerberos admin). Replace <source> with a host or subnet.

New-NetFirewallRule -DisplayName "Allow Kerberos admin 749/UDP" -Direction Inbound -Action Allow -Protocol UDP -LocalPort 749 -RemoteAddress <source>

Inbound UDP 749 (Kerberos admin). 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.