扫描某个网段下存活的IP：fping

前言：

之前用arp统计过某网段下的ip，但是有可能统计不全。网络管理平台又不允许登录。想要知道当前的ip占用情况，可以使用fping

fping命令类似于ping，但比ping更强大。与ping需要等待某一主机连接超时或发回反馈信息不同，fping在给一个主机发送完数据包后，马上给下一个主机发送数据包，实现多主机同时ping。同时，fping还可以在命令行中指定要ping的主机数量范围。

但是当某台主机或者交换机的网络策略禁用ICMP或者禁止ping包的时候，那就无法通过此方法来获取局域网中被占用的具体ip

使用方式：

ping指定的多个IP：

fping 192.168.3.1 192.168.3.12 192.168.3.16 2>/dev/null

ping整个网段：

fping -g 192.168.3.0/24 2>/dev/null

ping整个网段，只显示存活的主机：

fping -ag 192.168.3.0/24 2>/dev/null

ping某一段IP：

fping -ag 192.168.0.5 192.168.0.130 2>/dev/null

ping的具体选项目

Usage: fping [options] [targets...]

Probing options:
   -4, --ipv4         only ping IPv4 addresses
   -6, --ipv6         only ping IPv6 addresses
   -b, --size=BYTES   amount of ping data to send, in bytes (default: 56)
   -B, --backoff=N    set exponential backoff factor to N (default: 1.5)
   -c, --count=N      count mode: send N pings to each target
   -f, --file=FILE    read list of targets from a file ( - means stdin)
   -g, --generate     generate target list (only if no -f specified)
                      (give start and end IP in the target list, or a CIDR address)
                      (ex. fping -g 192.168.1.0 192.168.1.255 or fping -g 192.168.1.0/24)
   -H, --ttl=N        set the IP TTL value (Time To Live hops)
   -I, --iface=IFACE  bind to a particular interface
   -l, --loop         loop mode: send pings forever
   -m, --all          use all IPs of provided hostnames (e.g. IPv4 and IPv6), use with -A
   -M, --dontfrag     set the Don't Fragment flag
   -O, --tos=N        set the type of service (tos) flag on the ICMP packets
   -p, --period=MSEC  interval between ping packets to one target (in ms)
                      (in loop and count modes, default: 1000 ms)
   -r, --retry=N      number of retries (default: 3)
   -R, --random       random packet data (to foil link data compression)
   -S, --src=IP       set source address
   -t, --timeout=MSEC individual target initial timeout (default: 500 ms,
                      except with -l/-c/-C, where it's the -p period up to 2000 ms)

Output options:
   -a, --alive        show targets that are alive
   -A, --addr         show targets by address
   -C, --vcount=N     same as -c, report results in verbose format
   -D, --timestamp    print timestamp before each output line
   -e, --elapsed      show elapsed time on return packets
   -i, --interval=MSEC  interval between sending ping packets (default: 10 ms)
   -n, --name         show targets by name (-d is equivalent)
   -N, --netdata      output compatible for netdata (-l -Q are required)
   -o, --outage       show the accumulated outage time (lost packets * packet interval)
   -q, --quiet        quiet (don't show per-target/per-ping results)
   -Q, --squiet=SECS  same as -q, but show summary every n seconds
   -s, --stats        print final stats
   -u, --unreach      show targets that are unreachable
   -v, --version      show version
   -x, --reachable=N  shows if >=N hosts are reachable or not