Users report intermittent packet loss on a server and you suspect a faulty cable or duplex mismatch. Which command displays the per-interface packet, error, drop and collision counters for eth0 using iproute2?
LPIC-1 Exam 102-500, objective 109. Networking fundamentals medium
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How these questions are written — where each question comes from, what the verification ledger records, and what happens when one is found wrong.
The options
Correct ip -s link show eth0
Correct. The -s (statistics) switch makes ip print the RX and TX counters the kernel keeps for the device: packets, bytes, errors, dropped, overrun and carrier or collision counts.
Not correct ip -d link show eth0
Wrong. -d asks for extra device details, such as the link type and driver-specific parameters of a VLAN, bridge or tunnel. It adds no traffic counters.
Not correct ip -br addr show eth0
Wrong. -br prints a brief, one-line-per-interface table of names, states and addresses. It is a formatting option for readability, not a source of error statistics.
Not correct ss -i eth0
Wrong. ss reports on sockets, not network devices, and -i prints internal TCP information such as congestion window and RTT for each socket. It also takes filter expressions rather than an interface name in that position.
Why
Device-level counters distinguish a physical or driver problem from an application problem: rising RX errors or carrier errors point at cabling, duplex or the NIC, while rising dropped counts often point at a full queue. `ip -s link` is the iproute2 view of the same counters that the legacy `netstat -i` and `ifconfig` output show. Adding -s twice (`ip -s -s link`) expands the per-error-type breakdown.
Where this comes from
- Cited
- manual page ip(8)
Practise this
Reading one question is not practice. The trainer will draw a short set from objective 109 and space the ones you get wrong.
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