LVM、网络协议和管理
1.创建逻辑卷
创建物理卷
pvcreate /dev/sd{b1,c}
创建卷组名
vgcreate vg0 /dev/sd{b1,c} -s 4G
创建逻辑卷
lvcreate -n mysql -L 8G vg0
创建文件系统
mkfs.xfs /dev/vg0/mysql
挂载
mount /dev/vg0/mysql /mnt/mysql/
扩展文件系统
lvextend -l +1534 /dev/vg0/mysql
同步XFS文件系统
xfs_growfs /mnt/mysql/
扩展逻辑卷VG0的大小
vgextend vg0 /dev/sdd
同步EXT系列的文件系统
resize2fs /dev/vg0/binlog
可以扩展的同时直接同步文件系统，一条命令完成。
[root@centos7 ~]#lvextend -r -l +500 /dev/vg0/mysql
缩减逻辑分区的大小，缩减只能缩减EXT系列的。先取消挂载。
[root@centos7 ~]#umount /mnt/biglog/
检查文件的完整性
e2fsck -f /dev/vg0/binlog
缩减文件系统大小到10G
resize2fs /dev/vg0/binlog 10G
缩减逻辑卷大小到10G，有风险，可能丢失数据
[root@centos7 ~]#lvreduce -L 10G /dev/vg0/binlog
然后在挂载上，就可以完成缩减
[root@centos7 ~]#mount /dev/vg0/binlog /mnt/biglog/2.迁移逻辑卷，先取消挂载
先禁用，
[root@centos7 ~]#vgchange -an vg0
查看状态
[root@centos7 ~]#lvdisplay
导出状态
[root@centos7 ~]#vgexport vg0
就可以拔出硬盘了。插到新的机子上
然后导入
[root@centos7 ~]#vgimport vg0
启用，
[root@centos7 ~]#vgchange -ay vg0
然后挂载就可以使用了。3.移出逻辑卷的硬盘
增加物理卷
[root@centos7 ~]#pvcreate /dev/sdb4
加到VG0里
[root@centos7 ~]#vgextend vg0 /dev/sdb4
把sdc上的迁移到其他地方
[root@centos7 ~]#pvmove /dev/sdc
把sdc移出VG0
[root@centos7 ~]#vgreduce vg0 /dev/sdc
把上面的物理卷标识去掉，现在就是一块普通硬盘了
[root@centos7 ~]#pvremove /dev/sdc
4.删除逻辑卷
[root@centos7 ~]#umount /mnt/mysql/
[root@centos7 ~]#lvremove /dev/vg0/mysql
[root@centos7 ~]#vgremove vg0
[root@centos7 ~]#pvs
PV VG Fmt Attr PSize PFree
/dev/sdb1 lvm2 --- 4.00g 4.00g
/dev/sdb3 lvm2 --- 2.00g 2.00g
/dev/sdb4 lvm2 --- 5.00g 5.00g
/dev/sdd lvm2 --- 20.00g 20.00g
[root@centos7 ~]#pvremove /dev/sdd5.创建逻辑卷快照和使用。xfs文件系统的。
-n 名字 -s 逻辑卷标志 -L 逻辑卷大小 -p r 只读属性 最后指定是谁的快照。只读不可以挂载,和原来的UUID一样。强行挂载要不是只读模式， -o nouuid 不检查UUID
[root@centos7 ~]#lvcreate -n mysql_snapshot -s -L 1G -p r /dev/vg0/mysql
[root@centos7 ~]#mount -o nouuid /dev/vg0/mysql_snapshot2 /mnt/snap/
还原快照。逻辑卷快照消失，只能使用一次。
[root@centos7 ~]#umount /mut/snap/
[root@centos7 ~]#umount /mnt/mysql
[root@centos7 ~]#lvconvert --merge /dev/vg0/mysql_sanpshotext系列不存在UUID重复的情况，快照也可以只读
6.创建一个至少有两个PV组成的大小为20G的名为testvg的VG；要求PE大小为16MB, 而后在卷组中创建大小为5G的逻辑卷testlv；挂载至/users目录
[root@centos7 ~]#pvcreate /dev/sd{c,d1}
[root@centos7 ~]#pvdisplay
"/dev/sdd1" is a new physical volume of "10.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdd1
VG Name
PV Size 10.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID NYoBim-Wdxw-Bhak-hOiN-1WpU-2oOJ-2uzmPT
"/dev/sdc" is a new physical volume of "10.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdc
VG Name
PV Size 10.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID dIJhEo-YoxY-PGwh-Y1NS-17w2-UWcB-D25ABX
[root@centos7 ~]#vgcreate testvg /dev/sd{c,d1} -s 16MB
Volume group "testvg" successfully created[root@centos7 ~]#vgdisplay
--- Volume group ---
VG Name testvg
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 1
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 0
Open LV 0
Max PV 0
Cur PV 2
Act PV 2
VG Size <19.97 GiB
PE Size 16.00 MiB
Total PE 1278
Alloc PE / Size 0 / 0
Free PE / Size 1278 / <19.97 GiB
VG UUID Gy8wH6-XidI-D69o-pMiy-i8OX-P03i-HtjH72
[root@centos7 ~]#lvcreate -n testlv -L 5G testvg
WARNING: xfs signature detected on /dev/testvg/testlv at offset 0. Wipe it? [y/n]: y
Wiping xfs signature on /dev/testvg/testlv.
Logical volume "testlv" created.
[root@centos7 ~]#lvdisplay
--- Logical volume ---
LV Path /dev/testvg/testlv
LV Name testlv
VG Name testvg
LV UUID wkn8n8-B2GI-Aqf4-gTWz-tg8E-4bF5-YkAF01
LV Write Access read/write
LV Creation host, time centos7.5.localdomain, 2019-08-11 22:00:57 +0800
LV Status available
# open 0
LV Size 5.00 GiB
Current LE 320
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:0
[root@centos7 ~]#mkfs.ext4 /dev/testvg/testlv
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
327680 inodes, 1310720 blocks
65536 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=1342177280
40 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done [root@centos7 ~]#mount /dev/testvg/testlv /users7.新建用户archlinux，要求其家目录为/users/archlinux，而后su切换至archlinux用户，复制/etc/pam.d目录至自己的家目录
[archlinux@centos7 ~]$cp -r /etc/pam.d/ ./
[archlinux@centos7 ~]$ll
total 4
drwxr-xr-x 2 archlinux archlinux 4096 Aug 11 22:09 pam.d
[archlinux@centos7 ~]$pwd
/users/archlinux8.扩展testlv至7G，要求archlinux用户的文件不能丢失
[root@centos7 ~]#lvextend -r -L +2G /dev/testvg/testlv
Size of logical volume testvg/testlv changed from 5.00 GiB (320 extents) to 7.00 GiB (448 extents).
Logical volume testvg/testlv successfully resized.
resize2fs 1.42.9 (28-Dec-2013)
Filesystem at /dev/mapper/testvg-testlv is mounted on /users; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 1
The filesystem on /dev/mapper/testvg-testlv is now 1835008 blocks long.
[root@centos7 ~]#lvdisplay
--- Logical volume ---
LV Path /dev/testvg/testlv
LV Name testlv
VG Name testvg
LV UUID wkn8n8-B2GI-Aqf4-gTWz-tg8E-4bF5-YkAF01
LV Write Access read/write
LV Creation host, time centos7.5.localdomain, 2019-08-11 22:00:57 +0800
LV Status available
# open 1
LV Size 7.00 GiB
Current LE 448
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:09.收缩testlv至3G，要求archlinux用户的文件不能丢失
[root@centos7 ~]#umount /users
[root@centos7 ~]#resize2fs /dev/testvg/testlv 3G
resize2fs 1.42.9 (28-Dec-2013)
Please run 'e2fsck -f /dev/testvg/testlv' first.
[root@centos7 ~]#e2fsck -f /dev/testvg/testlv
e2fsck 1.42.9 (28-Dec-2013)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/testvg/testlv: 70/458752 files (0.0% non-contiguous), 67380/1835008 blocks
[root@centos7 ~]#resize2fs /dev/testvg/testlv 3G
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/testvg/testlv to 786432 (4k) blocks.
The filesystem on /dev/testvg/testlv is now 786432 blocks long.
[root@centos7 ~]#lvreduce -L 3G /dev/testvg/testlv
WARNING: Reducing active logical volume to 3.00 GiB.
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce testvg/testlv? [y/n]: y
Size of logical volume testvg/testlv changed from 7.00 GiB (448 extents) to 3.00 GiB (192 extents).
Logical volume testvg/testlv successfully resized.
[root@centos7 ~]#mount /dev/testvg/testlv /users10.对testlv创建快照，并尝试基于快照备份数据，验证快照的功能
-p r 设置只读模式，忘记添加了
[root@centos7 ~]#lvcreate -L 1G -s -n snap1 /dev/testvg/testlv
[root@centos7 ~]#umount /users
[root@centos7 ~]#lvdisplay
--- Logical volume ---
LV Path /dev/testvg/testlv
LV Name testlv
VG Name testvg
LV UUID wkn8n8-B2GI-Aqf4-gTWz-tg8E-4bF5-YkAF01
LV Write Access read/write
LV Creation host, time centos7.5.localdomain, 2019-08-11 22:00:57 +0800
LV snapshot status source of
snap1 [active]
LV Status available
# open 0
LV Size 3.00 GiB
Current LE 192
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:0
--- Logical volume ---
LV Path /dev/testvg/snap1
LV Name snap1
VG Name testvg
LV UUID KdGZPM-BqYW-GxDz-bOor-fmNE-Isdh-T7hsHo
LV Write Access read/write
LV Creation host, time centos7.5.localdomain, 2019-08-11 22:23:36 +0800
LV snapshot status active destination for testlv
LV Status available
# open 0
LV Size 3.00 GiB
Current LE 192
COW-table size 1.00 GiB
COW-table LE 64
Allocated to snapshot 0.01%
Snapshot chunk size 4.00 KiB
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:3
[root@centos7 ~]#lvconvert --merge /dev/testvg/snap1
Merging of volume testvg/snap1 started.
testvg/testlv: Merged: 100.00%11.Ethernet II以太网帧格式：
目标MAC 源MAC 类型 数据 FCS
6字节 6字节 2字节 46-1500字节 4字节
所以最小6+6+2+46+4 = 64，最大6+6+2+1500+4 = 1518。
（注：ISL封装后可达1548字节，802.1Q封装后可达1522字节）12.⽤正则表达式匹配邮件地址和⽹站？
egrep "[[:alnum:] ]+@[[:alnum:]]+\.com"
egrep "^([a-zA-Z0-9_-\.]([a-zA-Z0-9_-]{0,61}[a-zA-Z0-9_-])?\.)+[a-zA-Z]{1,6}$"13.查看端口被那几个应用占用
[root@centos7 ~]#ss -ntlp |grep 22
LISTEN 0 5 192.168.122.1:53 *:* users:(("dnsmasq",pid=7269,fd=6))
LISTEN 0 128 *:22 *:* users:(("sshd",pid=6780,fd=3))
LISTEN 0 128 :::22 :::* users:(("sshd",pid=6780,fd=4))
[root@centos7 ~]#lsof -i :22
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
sshd 6780 root 3u IPv4 43799 0t0 TCP *:ssh (LISTEN)
sshd 6780 root 4u IPv6 43801 0t0 TCP *:ssh (LISTEN)
sshd 11386 root 3u IPv4 97622 0t0 TCP 192.168.38.103:ssh->192.168.38.1:61967 (ESTABLISHED)
sshd 15611 root 3u IPv4 149223 0t0 TCP 192.168.38.103:ssh->192.168.38.1:64099 (ESTABLISHED)
sshd 16049 root 3u IPv4 152899 0t0 TCP 192.168.38.103:ssh->192.168.38.1:64967 (ESTABLISHED)
sshd 16283 root 3u IPv4 155757 0t0 TCP centos7.6.localdomain:ssh->172.18.1.77:65180 (ESTABLISHED)14.用户改名
修改文件
[root@7 ~]#vim /etc/sysconfig/network
HOSTNAME=7.6centos.localdomain
[root@7 ~]#hostname 7.6centos.localdomain
[root@7 ~]#exit
在这个地方添加新的名字，防止自己ping不通自己
[root@7 ~]#vim /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4 7.6centos.localdomain
[root@7 ~]#ping 7.6centos.localdomain15.配置eth1⽹卡地址为1.1.1.1/24
直接就改了
[root@centos7 ~]#ifconfig eth1 172.18.7.7/24 up[root@centos7 ~]#ifconfig eth1 1.1.1.1 netmask 255.255.255.016.激活eth1⽹卡，关闭网卡
[root@centos7 ~]#ifconfig eth1 down
[root@centos7 ~]#ifconfig eth1 up17.配置eth1的⽹卡别名为eth1:0，ip为10.0.0.100
[root@centos7 ~]#ifconfig eth1:0 10.0.0.100/24 up
[root@centos7 ~]#ifconfig eth1:0
eth1:0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 10.0.0.100 netmask 255.255.255.0 broadcast 10.0.0.255
ether 00:0c:29:a3:3e:ce txqueuelen 1000 (Ethernet)
[root@centos7 ~]#ifconfig eth1:0 10.0.0.100/24 down17.添加到1.1.1.1的主机路由，下⼀跳为172.18.0.1
[root@centos7 ~]#route add -host 1.1.1.1 gw 172.18.0.1
[root@centos7 ~]#route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 172.18.0.1 0.0.0.0 UG 100 0 0 eth0
0.0.0.0 172.18.0.1 0.0.0.0 UG 101 0 0 eth1
1.1.1.1 172.18.0.1 255.255.255.255 UGH 0 0 0 eth0
172.18.0.0 0.0.0.0 255.255.0.0 U 100 0 0 eth0
172.18.0.0 0.0.0.0 255.255.0.0 U 101 0 0 eth1
192.168.122.0 0.0.0.0 255.255.255.0 U 0 0 0 virbr018.删除主机路由1.1.1.1
[root@centos7 ~]#route del -host 1.1.1.1
[root@centos7 ~]#route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 172.18.0.1 0.0.0.0 UG 100 0 0 eth0
0.0.0.0 172.18.0.1 0.0.0.0 UG 101 0 0 eth1
172.18.0.0 0.0.0.0 255.255.0.0 U 100 0 0 eth0
172.18.0.0 0.0.0.0 255.255.0.0 U 101 0 0 eth1
192.168.122.0 0.0.0.0 255.255.255.0 U 0 0 0 virbr019.添加到1.1.1.0/24的⽹络路由，下⼀跳为172.18.0.1
[root@centos7 ~]#route add -net 1.1.1.0/24 gw 172.18.0.1 dev eth0
[root@centos7 ~]#route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 172.18.0.1 0.0.0.0 UG 100 0 0 eth0
0.0.0.0 172.18.0.1 0.0.0.0 UG 101 0 0 eth1
1.1.1.0 172.18.0.1 255.255.255.0 UG 0 0 0 eth0
172.18.0.0 0.0.0.0 255.255.0.0 U 100 0 0 eth0
172.18.0.0 0.0.0.0 255.255.0.0 U 101 0 0 eth1
192.168.122.0 0.0.0.0 255.255.255.0 U 0 0 0 virbr020.添加到1.1.1.0/24的⽹络路由，下⼀跳为172.18.0.1
[root@centos7 ~]#route add -net 1.1.1.0 netmask 255.255.255.0 gw 172.18.0.1 dev eth121.添加默认路由
[root@centos7 ~]#route add -net 0.0.0.0 netmask 0.0.0.0 gw 172.18.0.1
[root@centos7 ~]#route add default gw 172.18.0.122.禁⽤ens38⽹卡
[root@centos7 ~]#ip link set dev eth1 down23.查看eth1⽹卡的状态
[root@centos7 ~]#ip link show dev eth1
3: eth1: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 1000
link/ether 00:0c:29:a3:3e:ce brd ff:ff:ff:ff:ff:ff24.启⽤eth1⽹卡
[root@centos7 ~]#ip link set dev eth1 up
[root@centos7 ~]#ip link show
[root@centos7 ~]#ip link show dev eth1
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
link/ether 00:0c:29:a3:3e:ce brd ff:ff:ff:ff:ff:ff25.删除网卡地址和添加网卡地址
[root@centos7 ~]#ip addr del 172.18.7.7 dev eth1
Warning: Executing wildcard deletion to stay compatible with old scripts.
Explicitly specify the prefix length (172.18.7.7/32) to avoid this warning.
This special behaviour is likely to disappear in further releases,
fix your scripts!
[root@centos7 ~]#ip addr add 172.18.7.7/24 dev eth1 26.配置eth1⽹卡别名为ens38:0，地址为4.4.4.4/24和删除
[root@centos7 ~]#ip addr add 4.4.4.4 dev eth1 label eth1:0
eth1:0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 4.4.4.4 netmask 255.255.255.255 broadcast 0.0.0.0
ether 00:0c:29:a3:3e:ce txqueuelen 1000 (Ethernet)
[root@centos7 data]#ifconfig eth1:1 1.1.1.1/24
[root@centos7 ~]#ip add flush dev eth1 label eth1:027.删除eth1⽹卡上的使⽤ip地址和增加
[root@centos7 ~]#ip addr flush dev eth1
[root@centos7 ~]#ip addr add 172.18.7.7 dev eth128.查看路由表
[root@centos7 data]#ip route show
default via 172.18.0.1 dev eth0
default via 172.18.0.1 dev eth0 proto static metric 100
1.1.1.0/24 via 172.18.0.1 dev eth0
172.18.0.0/16 dev eth0 proto kernel scope link src 172.18.7.127 metric 100
192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1
[root@centos7 data]#ip route list
default via 172.18.0.1 dev eth0
default via 172.18.0.1 dev eth0 proto static metric 100
1.1.1.0/24 via 172.18.0.1 dev eth0
172.18.0.0/16 dev eth0 proto kernel scope link src 172.18.7.127 metric 100
192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.129.添加⽹络路由192.168.0.0/24
[root@centos7 data]#ip route add 192.168.0.0/24 via 172.18.0.130.添加默认⽹关和删除
[root@centos7 data]#ip route add default via 172.18.0.1
[root@centos7 data]#route add default gw 172.18.0.1
指定端口
ip route add default via 172.18.0.1 dev eth0
[root@centos7 data]#ip route del default via 172.18.0.1
[root@centos7 data]#route del default gw 172.18.0.1 dev eth031.配置dns⽂件，地址为172.18.0.1，重启永久⽣效
[root@centos7 data]#vim /etc/resolv.conf 32.查看tcp协议，⽤数⼦显⽰ip和端⼝，所有状态⽹络连接
[root@centos7 data]#netstat -tan
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:6000 0.0.0.0:* LISTEN
tcp 0 0 192.168.122.1:53 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:37698 0.0.0.0:* LISTEN
tcp 0 0 172.18.7.7:22 172.18.1.77:56968 ESTABLISHED
tcp 0 52 172.18.7.127:22 172.18.1.77:51868 ESTABLISHED
tcp6 0 0 :::111 :::* LISTEN
tcp6 0 0 :::6000 :::* LISTEN
tcp6 0 0 :::80 :::* LISTEN
tcp6 0 0 :::46709 :::* LISTEN
tcp6 0 0 :::22 :::* LISTEN
tcp6 0 0 ::1:631 :::* LISTEN
tcp6 0 0 ::1:25 :::* LISTEN 33.查看udp协议，⽤数⼦显⽰ip和端⼝，所有状态⽹络连接
[root@centos7 data]#netstat -uan
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
udp 0 0 0.0.0.0:967 0.0.0.0:*
udp 0 0 127.0.0.1:1005 0.0.0.0:*
udp 0 0 192.168.122.1:53 0.0.0.0:*
udp 0 0 0.0.0.0:67 0.0.0.0:*
udp 0 0 0.0.0.0:111 0.0.0.0:*
udp 0 0 0.0.0.0:5353 0.0.0.0:*
udp 0 0 0.0.0.0:50817 0.0.0.0:*
udp 0 0 0.0.0.0:52965 0.0.0.0:*
udp6 0 0 :::967 :::*
udp6 0 0 :::111 :::*
udp6 0 0 :::54851 :::* 34.查看tcp协议，⽤数⼦显⽰ip和端⼝，所有处于监听状态⽹络连接
[root@centos7 data]#netstat -tnl
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:6000 0.0.0.0:* LISTEN
tcp 0 0 192.168.122.1:53 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:37698 0.0.0.0:* LISTEN
tcp6 0 0 :::111 :::* LISTEN
tcp6 0 0 :::6000 :::* LISTEN
tcp6 0 0 :::80 :::* LISTEN
tcp6 0 0 :::46709 :::* LISTEN
tcp6 0 0 :::22 :::* LISTEN
tcp6 0 0 ::1:631 :::* LISTEN
tcp6 0 0 ::1:25 :::* LISTEN 35.查看udp协议，⽤数⼦显⽰ip和端⼝，所有处于监听状态⽹络连接
[root@centos7 data]#netstat -unl
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
udp 0 0 0.0.0.0:967 0.0.0.0:*
udp 0 0 127.0.0.1:1005 0.0.0.0:*
udp 0 0 192.168.122.1:53 0.0.0.0:*
udp 0 0 0.0.0.0:67 0.0.0.0:*
udp 0 0 0.0.0.0:111 0.0.0.0:*
udp 0 0 0.0.0.0:5353 0.0.0.0:*
udp 0 0 0.0.0.0:50817 0.0.0.0:*
udp 0 0 0.0.0.0:52965 0.0.0.0:*
udp6 0 0 :::967 :::*
udp6 0 0 :::111 :::*
udp6 0 0 :::54851 :::* 36.显⽰所有接⼝统计数据
[root@centos7 data]#netstat -i
Kernel Interface table
Iface MTU RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg
eth0 1500 78298 0 0 0 6449 0 0 0 BMRU
eth1 1500 44702 0 0 0 314 0 0 0 BMRU
lo 65536 210 0 0 0 210 0 0 0 LRU
virbr0 1500 0 0 0 0 0 0 0 0 BMU37.显⽰eth0接⼝是流量数据
[root@centos7 data]#netstat -I=eth0
Kernel Interface table
Iface MTU RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg
eth0 1500 78518 0 0 0 6478 0 0 0 BMRU[root@centos7 data]#ifconfig -s eth0
Iface MTU RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg
eth0 1500 78621 0 0 0 6502 0 0 0 BMRU38.centos6重启⽹络服务和关闭NetworkManager服务
service network restart
service NetworkManager stop39.查看具体路由信息
[root@centos7 data]#traceroute www.baidu.com
traceroute to www.baidu.com (61.135.169.121), 30 hops max, 60 byte packets
1 gateway (172.18.0.1) 1.235 ms 1.118 ms 1.030 ms
2 192.168.0.1 (192.168.0.1) 0.918 ms 0.813 ms 0.728 ms
3 123.118.208.1 (123.118.208.1) 5.181 ms 5.068 ms 4.984 ms
4 114.244.95.105 (114.244.95.105) 4.177 ms 61.148.163.181 (61.148.163.181) 7.078 ms 61.148.163.81 (61.148.163.81) 4.690 ms
5 61.148.157.229 (61.148.157.229) 5.187 ms 3.714 ms 4.964 ms[root@centos7 data]#tracepath 114.114.114.114
1?: [LOCALHOST] pmtu 1500
1: gateway 3.093ms
1: gateway 1.891ms
2: 192.168.0.1 2.132ms
3: 192.168.0.1 2.609ms pmtu 1480
3: 123.118.208.1 18.058ms
4: 114.244.95.61 3.921ms
5: no reply
6: 125.33.186.5 16.844ms
7: 219.158.4.230 13.296ms
^C[root@centos7 data]#mtr www.baidu.com40.子网掩码不同，网络IP可能是会不一样的
A:192.168.38.100/25
B:192.168.38.200/24
A--->B
192.168.38.100与255.255.255.128=192.168.38.0
192.168.38.200与255.255.255.128=192.168.38.128
不相同
B--->A
192.168.38.100与255.255.255.0=192.168.38.0
192.168.38.200与255.255.255.0=192.168.38.041.高于DNS的名字解析，测试时用。改名字时最好后面也加一个。
[root@centos7 data]#vim /etc/hosts42.抓包。-nn转化为数字形式
[root@centos7 network-scripts]#tcpdump -i eth0 -nn icmp
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
16:33:22.816999 IP 172.25.0.111 > 192.168.66.111: ICMP echo request, id 6893, seq 55, length 64
16:33:22.817030 IP 192.168.66.111 > 172.25.0.111: ICMP echo reply, id 6893, seq 55, length 6443.查看最新日志。
[root@centos7 data]#tail /var/log/messages
Aug 17 16:34:32 centos7 avahi-daemon[6307]: Invalid legacy unicast query packet.
Aug 17 16:34:32 centos7 avahi-daemon[6307]: Received response from host 172.18.144.184 with invalid source port 50556 on interface 'eth0.0'
Aug 17 16:34:32 centos7 avahi-daemon[6307]: Invalid legacy unicast query packet.
Aug 17 16:34:32 centos7 avahi-daemon[6307]: Received response from host 172.18.144.184 with invalid source port 50556 on interface 'eth0.0'
Aug 17 16:34:32 centos7 avahi-daemon[6307]: Invalid legacy unicast query packet.
Aug 17 16:34:32 centos7 avahi-daemon[6307]: Received response from host 172.18.144.184 with invalid source port 50556 on interface 'eth0.0'
Aug 17 16:34:33 centos7 avahi-daemon[6307]: Received response from host 172.18.144.184 with invalid source port 50556 on interface 'eth0.0'
Aug 17 16:34:34 centos7 avahi-daemon[6307]: Received response from host 172.18.144.184 with invalid source port 50556 on interface 'eth0.0'
Aug 17 16:34:34 centos7 avahi-daemon[6307]: Received response from host 172.18.144.184 with invalid source port 50556 on interface 'eth0.0'
Aug 17 16:34:36 centos7 avahi-daemon[6307]: Received response from host 172.18.144.184 with invalid source port 50556 on interface 'eth0.0'44.ping -l 指定从哪个网卡访问。
[root@centos7 data]#ping -l 172.18.7.7 114.114.114.114
PING 114.114.114.114 (114.114.114.114) 56(84) bytes of data.
64 bytes from 114.114.114.114: icmp_seq=1 ttl=86 time=12.6 ms
64 bytes from 114.114.114.114: icmp_seq=2 ttl=89 time=12.5 ms45.-0.3秒查看一次网卡吞吐量 。-i必须和后面的连在一起，指定网卡
[root@centos7 data]#watch -n0.3 netstart -leth046.centos6上支持补全的包。。。。。退出重进生效
yum install bash-completion46.显示IP和mcp地址对应的关系
[root@centos7 data]#arp -n
Address HWtype HWaddress Flags Mask Iface
172.18.0.1 ether 14:6b:9c:bd:6b:cd C eth0
172.18.1.77 ether 98:e7:f4:68:64:aa C eth0
[root@centos7 data]#ip neigh
172.18.0.1 dev eth0 lladdr 14:6b:9c:bd:6b:cd STALE
172.18.1.77 dev eth0 lladdr 98:e7:f4:68:64:aa REACHABLE