82 lines
2.4 KiB
Markdown
82 lines
2.4 KiB
Markdown
# Network
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Test hostname resolution with `getent`, for example `getent hosts www.psi.ch`. Unlike `nslookup` or `dig`, it uses the
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system resolver.
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The systems IP addresses and routes can be displayed using `ip`:
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```bash
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[root@lx ~]# ip address
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1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
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link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
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inet 127.0.0.1/8 scope host lo
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valid_lft forever preferred_lft forever
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inet6 ::1/128 scope host
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valid_lft forever preferred_lft forever
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2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
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link/ether 00:50:56:9d:6d:03 brd ff:ff:ff:ff:ff:ff
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inet 10.129.160.195/24 brd 10.129.160.255 scope global ens160
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valid_lft forever preferred_lft forever
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inet6 fe80::250:56ff:fe9d:6d03/64 scope link
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valid_lft forever preferred_lft forever
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[root@lx ~]# ip route
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default via 10.129.160.1 dev ens160
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10.129.160.0/24 dev ens160 proto kernel scope link src 10.129.160.195
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169.254.0.0/16 dev ens160 scope link metric 1002
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```
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The link status and other information of an interface can be displayed using
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`ethtool`:
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1. Link status:
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```bash
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[root@lx ~]# ethtool ens160
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Settings for ens160:
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[...]
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Speed: 10000Mb/s
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Duplex: Full
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[...]
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Link detected: yes
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```
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2. Statistics (driver-specific, but look for errors/discards/dropped)::
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```bash
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[root@lx ~]# ethtool -S ens160
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NIC statistics:
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Tx Queue#: 0
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TSO pkts tx: 21529
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TSO bytes tx: 91036062
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ucast pkts tx: 1036632
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ucast bytes tx: 235421707
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mcast pkts tx: 8
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mcast bytes tx: 648
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bcast pkts tx: 7
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bcast bytes tx: 294
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pkts tx err: 0
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pkts tx discard: 0
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drv dropped tx total: 0
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too many frags: 0
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giant hdr: 0
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hdr err: 0
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tso: 0
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ring full: 0
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pkts linearized: 0
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hdr cloned: 0
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giant hdr: 0
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Rx Queue#: 0
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LRO pkts rx: 6913
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LRO byte rx: 100534073
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ucast pkts rx: 551554
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ucast bytes rx: 161369441
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mcast pkts rx: 4
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mcast bytes rx: 344
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bcast pkts rx: 753276
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bcast bytes rx: 45787629
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pkts rx OOB: 0
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pkts rx err: 0
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drv dropped rx total: 0
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err: 0
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fcs: 0
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rx buf alloc fail: 0
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tx timeout count: 0
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``` |