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Use the systemd suite of commands and not deprecated init.d commands or other deprecated commands, to manage networking.
networkctlnetmgrFor information about tcpdump and netcat, see Installing the Packages for tcpdump and netcat with tdnf
The network service, which is enabled by default, starts when the system boots. You manage the network service by using systemd commands, such as systemd-networkd, systemd-resolvd, and networkctl.
You can check the status of the network service by running the following command:
systemctl status systemd-networkd
The following is a result of the command:
* systemd-networkd.service - Network Service
Loaded: loaded (/usr/lib/systemd/system/systemd-networkd.service; enabled; vendor preset: enabled)
Active: active (running) since Fri 2016-04-29 15:08:51 UTC; 6 days ago
Docs: man:systemd-networkd.service(8)
Main PID: 291 (systemd-network)
Status: "Processing requests..."
CGroup: /system.slice/systemd-networkd.service
`-291 /lib/systemd/systemd-networkd
VMware recommends that you use the ip or ss commands as the ifconfig and netstat commands are deprecated.
To display a list of network interfaces, run the ss command. Similarly, to display information for IP addresses, run the ip addr command.
Examples:
USE THIS IPROUTE COMMAND INSTEAD OF THIS NET-TOOL COMMAND
ip addr ifconfig -a
ss netstat
ip route route
ip maddr netstat -g
ip link set eth0 up ifconfig eth0 up
ip -s neigh arp -v
ip link set eth0 mtu 9000 ifconfig eth0 mtu 9000
Use the ip route version of a command instead of the net-tools to get accurate information:
ip neigh
198.51.100.2 dev eth0 lladdr 00:50:56:e2:02:0f STALE
198.51.100.254 dev eth0 lladdr 00:50:56:e7:13:d9 STALE
198.51.100.1 dev eth0 lladdr 00:50:56:c0:00:08 DELAY
arp -a
? (198.51.100.2) at 00:50:56:e2:02:0f [ether] on eth0
? (198.51.100.254) at 00:50:56:e7:13:d9 [ether] on eth0
? (198.51.100.1) at 00:50:56:c0:00:08 [ether] on eth0
Important: If you modify an IPv6 configuration or add an IPv6 interface, you must restart systemd-networkd. Traditional methods of using ifconfig commands will be inadequate to register the changes. Run the following command instead:
systemctl restart systemd-networkd
The networkctl command displays information about network connections that helps you configure networking services and troubleshoot networking problems.
You can progressively add options and arguments to the networkctl command to move from general information about network connections to specific information about a network connection.
Running networkctl without options defaults to the list command:
networkctl
IDX LINK TYPE OPERATIONAL SETUP
1 lo loopback carrier unmanaged
2 eth0 ether routable configured
3 docker0 ether routable unmanaged
11 vethb0aa7a6 ether degraded unmanaged
4 links listed.
Run the networkctl with the status command to display active network links with IP addresses for not only the Ethernet connection, but also the Docker container.
root@photon-rc [ ~ ]# networkctl status
* State: routable
Address: 198.51.100.131 on eth0
172.17.0.1 on docker0
fe80::20c:29ff:fe55:3ca6 on eth0
fe80::42:f0ff:fef7:bd81 on docker0
fe80::4c84:caff:fe76:a23f on vethb0aa7a6
Gateway: 198.51.100.2 on eth0
DNS: 198.51.100.2
You can add a network link, such as the Ethernet connection, as the argument of the status command to show specific information about the link:
root@photon-rc [ ~ ]# networkctl status eth0
* 2: eth0
Link File: /usr/lib/systemd/network/99-default.link
Network File: /etc/systemd/network/10-dhcp-en.network
Type: ether
State: routable (configured)
Path: pci-0000:02:01.0
Driver: e1000
HW Address: 00:0c:29:55:3c:a6 (VMware, Inc.)
MTU: 1500
Address: 198.51.100.131
fe80::20c:29ff:fe55:3ca6
Gateway: 198.51.100.2
DNS: 198.51.100.2
CLIENTID: ffb6220feb00020000ab116724f520a0a77337
You can add a Docker container as follows:
networkctl status docker0
* 3: docker0
Link File: /usr/lib/systemd/network/99-default.link
Network File: n/a
Type: ether
State: routable (unmanaged)
Driver: bridge
HW Address: 02:42:f0:f7:bd:81
MTU: 1500
Address: 172.17.0.1
fe80::42:f0ff:fef7:bd81
In the example above, the output indicates that state of the Docker container is unmanaged. Docker uses the bridge drive to handle managing the networking for the containers and not systemd-resolved or systemd-networkd.
For more information about networkctl commands and options, see https://www.freedesktop.org/software/systemd/man/networkctl.html.
You can set systemd-networkd to work in debug mode so that you can analyze log files with debugging information to help troubleshoot networking problems.
The following procedure turns on network debugging by adding a drop-in file in /etc/systemd to customize the default systemd configuration in /usr/lib/systemd.
Run the following command as root to create a directory with this exact name, including the .d extension:
mkdir -p /etc/systemd/system/systemd-networkd.service.d/
Run the following command as root to establish a systemd drop-in unit with a debugging configuration for the network service:
cat > /etc/systemd/system/systemd-networkd.service.d/10-loglevel-debug.conf << "EOF"
[Service]
Environment=SYSTEMD_LOG_LEVEL=debug
EOF
Reload the systemctl daemon and restart the systemd-networkd service for the changes to take effect:
systemctl daemon-reload
systemctl restart systemd-networkd
Verify that your changes took effect:
`systemd-delta --type=extended`
View the log files by running this command:
`journalctl -u systemd-networkd`
After debugging the network connections, turn debugging off by deleting the drop-in file:
rm /etc/systemd/system/systemd-networkd.service.d/10-loglevel-debug.conf
The design of Photon OS emphasizes security. On the minimal and full versions of Photon OS, the default security policy turns on the firewall and drops packets from external interfaces and applications. As a result, you might need to add rules to iptables to permit forwarding, allow protocols like HTTP, and open ports. In other words, you must configure the firewall for your applications and requirements.
The default iptables settings on the full version look like this:
iptables --list
Chain INPUT (policy DROP)
target prot opt source destination
ACCEPT all -- anywhere anywhere
ACCEPT all -- anywhere anywhere ctstate RELATED,ESTABLISHED
ACCEPT tcp -- anywhere anywhere tcp dpt:ssh
Chain FORWARD (policy DROP)
target prot opt source destination
Chain OUTPUT (policy DROP)
target prot opt source destination
ACCEPT all -- anywhere anywhere
To find out how to adjust the settings, see the man page for iptables.
Although the default iptables policy accepts SSH connections, the sshd configuration file on the full version of Photon OS is set to reject SSH connections. See Permitting Root Login with SSH.
If you are unable to ping a Photon OS machine, check the firewall rules. Verify if the rules allow connectivity for the port and protocol.
You can supplement the iptables commands by using lsof to, for instance, see the processes listening on ports:
lsof -i -P -n
If you are running a VMware appliance on Photon OS and the VAMI module has problems or if there are networking issues, you can use the Photon OS netmgr utility to inspect the networking settings. Make sure that the IP addresses for the DNS server and other infrastructure are correct. Use tcpdump to analyze the issues.
The error code that you get from netmgr is a standard Unix error code. Enter it into a search engine to obtain more information on the error.