Member Avatar for rkruz

How can I ping point to point, or ethernet to ethernet when there is no IP address assigned? Is that possible? I tried using a MAC address with Ping but that did not work. In this case its a PC to a ethernet to 100BaseF (fiber) conversion and I want to send pings to test the link (no other routers or switches involved, just point to point). Any insight appreciated

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  • Latest Post Latest Post by mdm7923

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— good question. and leaned toward IP-based testing; below are practical link‑layer and physical checks you can run when you want to test a direct Ethernet <-> fiber pair without assigning IPs.

Start with the physical/link layer (fast and often decisive). Check NIC/media‑converter LEDs, then query the interface for carrier, speed and counters. On Linux:

sudo ethtool eth0
ip link show dev eth0
cat /sys/class/net/eth0/carrier   # 1 = link, 0 = no link

Capture and generate raw Ethernet traffic. Use a packet sniffer to see whether any frames arrive, and send test frames if needed. Example capture:

sudo tcpdump -i eth0 -e -n

To generate frames without using IP, craft raw Ethernet frames (Scapy example — run as root):

from scapy.all import sendp, Ether
sendp(Ether(dst="ff:ff:ff:ff:ff:ff")/b"link-test", iface="eth0")

Fiber/media-converter specific checks (very common failure points): confirm both transceivers are the same type (MM vs SM and compatible wavelength), check connector type/polarity (TX/RX swap), try a short known-good patch or swap SFPs/media converters, and use a loopback plug on the fiber port to see if the local end reports link. If available, use SFP diagnostics/DOM or an optical power meter / visual fault locator to verify light and loss.

Quick troubleshooting order: 1) confirm LEDs/carrier, 2) try local loopback on each end (isolates faulty box vs cable), 3) swap cables/SFPs with known good parts, 4) capture frames and send raw L2 frames, 5) measure optical power if link still fails. Run these tests on non‑production equipment or during a maintenance window.

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Member Avatar for freshfitz

You can't. You basically have no network if you have no ip's

Member Avatar for mdm7923

you can't ping without an IP address. are you using this network to ping between PCs or access the internet. if you are only using it for testing you can assign a static IP address to each machine from the network configuration settings in the windows control panel, just right click and scroll down to TCP IP, then use a 192, 127, or 10 net address for your testing and a subnet mask of

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