Changing network interface speed with ethtool is not working
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Thanks to @Diamant. After digging more the one of the CABLE connecting server eth ports seems to be faulty and replacing it solved the problem.
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Updated on September 18, 2022Comments
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sherpaurgen almost 2 years
Im using lenevo M5 server which have Gbps ethernet cards, but strangely when i read cat /sys/class/net/eth3/speed it show 100 similarly when using ethtool it show 100Mbps only.The output of dmesg and ethtool are below. Any idea why is that
root@server1:~# dmesg |grep eth1 [ 3.027487] tg3 0000:16:00.1 eth1: Tigon3 [partno(BCM95769) rev 5719001] (PCI Express) MAC address 08:94:ef:5d:81:a2 [ 3.027497] tg3 0000:16:00.1 eth1: attached PHY is 5719C (10/100/1000Base-T Ethernet) (WireSpeed[1], EEE[1]) [ 3.027503] tg3 0000:16:00.1 eth1: RXcsums[1] LinkChgREG[0] MIirq[0] ASF[1] TSOcap[1] [ 3.027508] tg3 0000:16:00.1 eth1: dma_rwctrl[00000001] dma_mask[64-bit] [ 28.133071] bond0: Adding slave eth1 [ 28.249876] bond0: Enslaving eth1 as a backup interface with an up link [ 53.149602] tg3 0000:16:00.1 eth1: Link is up at 100 Mbps, full duplex [ 53.149620] tg3 0000:16:00.1 eth1: Flow control is off for TX and off for RX [ 53.149624] tg3 0000:16:00.1 eth1: EEE is disabled
# ethtool eth3
Settings for eth3: Supported ports: [ TP ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Half 1000baseT/Full Supported pause frame use: No Supports auto-negotiation: Yes Advertised link modes: 100baseT/Full Advertised pause frame use: Symmetric Advertised auto-negotiation: Yes Link partner advertised link modes: 100baseT/Half 100baseT/Full 1000baseT/Full Link partner advertised pause frame use: No Link partner advertised auto-negotiation: Yes Speed: 100Mb/s Duplex: Full Port: Twisted Pair PHYAD: 2 Transceiver: internal Auto-negotiation: on MDI-X: off Supports Wake-on: g Wake-on: g Current message level: 0x000000ff (255) drv probe link timer ifdown ifup rx_err tx_err Link detected: yes
When i try to change the speed with
ethtool -s eth3 speed 1000 duplex full
the "Speed " section is "Unknown" similarly reading(cat) the file /sys/class/net/eth3/speed gives invalid argument.-
Diamond almost 6 yearsJust to be sure, is your cabling ok? It should be a cat 5e at least with all 8 wires patched.
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sherpaurgen almost 6 years@Diamant Cat6 cable is used to connect the server's ethernet port to switch. Do you know possible reasons for this behaviour ?
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Ron Maupin almost 6 yearsThe cable category is relative unimportant as Category-5e will work at gigabit. What is important is that you have all four pairs (eight wires) properly connected. Gigabit requires the use of all four pairs, but if it only has two good pairs, then it falls back to 100 Mbps. I have seen many cable installations and/or patch cables that only use two pairs because that was all that was needed for 10/100 Mbps, and people were trying to save money on cabling, Unfortunately, it does not work with 1000 Mbps.
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sherpaurgen almost 6 yearsUnfortunately i dont have access to the network switch but when i asked datacenter technicians about port speed the answer was it was 1000Mbps. Do you know if there are other possible reasons for this problem ?
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mx1up almost 6 yearsmm.. not really.. but it can't be set to a fixed 1000Mbps since you are getting 100. maybe let them configure the fixed setting? (no negotation) Or have them change network cables to be sure they're not faulty.. but these are just guesses of course