命令行程序测试DHCP服务

是否有一个简单的类似于ping的命令来测试DHCP服务是否正在网络上运行？...在Linux上

即使您不使用Nagios监控服务器，也可以grep check_dhcp二进制文件或从源代码对其进行编译，然后使用该检查来测试DHCP服务器。例如

./check_dhcp -v -s <dhcp_server_address> -r <expected_ip_address> -m <mac_address_touse>

根据此答案，假设您已安装nmap（sudo apt install nmap）：

sudo nmap --script broadcast-dhcp-discover

-e $interface如果您具有多个网络接口，请添加该选项。（例如：nmap --script broadcast-dhcp-discover -e eth0）

样本输出：

Starting Nmap 7.01 ( https://nmap.org ) at 2017-09-27 17:40 CEST
Pre-scan script results:
| broadcast-dhcp-discover: 
|   Response 1 of 1: 
|     IP Offered: 192.168.81.94
|     DHCP Message Type: DHCPOFFER
|     Server Identifier: 192.168.81.2
|     IP Address Lease Time: 5m00s
|     Subnet Mask: 255.255.255.0
|     Router: 192.168.81.2
|     Domain Name Server: 192.168.81.2
|     Domain Name: example.lan
|     NTP Servers: 192.168.81.10, 192.168.81.2
|     NetBIOS Name Server: 192.168.81.10
|_    NetBIOS Node Type: 8
WARNING: No targets were specified, so 0 hosts scanned.
Nmap done: 0 IP addresses (0 hosts up) scanned in 0.66 seconds

或使用nmap v。6在另一个网络上的此输出：

Starting Nmap 6.00 ( http://nmap.org ) at 2017-09-27 17:42 CEST
Pre-scan script results:
| broadcast-dhcp-discover: 
|   IP Offered: 192.168.4.101
|   DHCP Message Type: DHCPOFFER
|   Server Identifier: 192.168.4.1
|   IP Address Lease Time: 7 days, 0:00:00
|   Subnet Mask: 255.255.255.0
|   Time Offset: 7200
|   Router: 192.168.4.1
|   Domain Name Server: 208.91.112.53, 208.91.112.52
|   Renewal Time Value: 3 days, 12:00:00
|_  Rebinding Time Value: 6 days, 3:00:00
WARNING: No targets were specified, so 0 hosts scanned.
Nmap done: 0 IP addresses (0 hosts up) scanned in 1.15 seconds

dhcpdump 非常适合在网络上嗅探和显示DHCP数据包。

例如

# dhcpdump -i eth0
---------------------------------------------------------------------------

  TIME: 2015-11-27 11:41:37.379
    IP: 0.0.0.0 (0:11:b9:5:0:b8) > 255.255.255.255 (ff:ff:ff:ff:ff:ff)
    OP: 1 (BOOTPREQUEST)
 HTYPE: 1 (Ethernet)
  HLEN: 6
  HOPS: 0
   XID: abce9327
  SECS: 0
 FLAGS: 0
CIADDR: 0.0.0.0
YIADDR: 0.0.0.0
SIADDR: 0.0.0.0
GIADDR: 0.0.0.0
CHADDR: 00:11:b9:05:00:b8:00:00:00:00:00:00:00:00:00:00
 SNAME: .
 FNAME: .
OPTION:  53 (  1) DHCP message type         1 (DHCPDISCOVER)
OPTION:  57 (  2) Maximum DHCP message size 576
OPTION:  55 (  4) Parameter Request List      1 (Subnet mask)
                          3 (Routers)
                         28 (Broadcast address)
                          6 (DNS server)

---------------------------------------------------------------------------

您可以将其与其他工具结合使用以进行DHCP请求，或者仅用于监视PC /设备查询DHCP。

或者您可以dhcpcd在测试模式下尝试：

dhcpcd -T eth0

我之前写了一个DHCP测试客户端程序，可在Windows和POSIX上运行：

https://github.com/Cyber​​Shadow/dhcptest

为什么不仅仅发出DHCP请求？

dhclient

对于详细输出，请使用：

dhclient -v

有一个名为dhcping的程序（只有一个p）

在Debian-Ubuntu系统上：

dhcpd -f

提供良好的反馈并测试配置。

在RH系统上，请尝试：

/etc/rc.d/init.d/dhcpd configtest

如果您使用nagios，则可以使用check_dhcp对其进行监视