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1 perry 1 nmicmpd
2 !!!nmicmpd
3 NAME
4 SYNOPSIS
5 DESCRIPTION
6 PROTOCOL
7 SEE ALSO
8 AUTHORS
9 ----
10 !!NAME
11
12
13 nmicmpd - The network management ICMP daemon.
14 !!SYNOPSIS
15
16
17 __nmicmpd__
18
19
20 ________________________________________________________________________________________________________________________________________
21 !!DESCRIPTION
22
23
24 The __nmicmpd__ daemon allows a user processes to send
25 ICMP messages (RFC 792, RFC 1122) to arbitrary hosts on the
26 Internet. The daemon reads requests from the standard input
27 and writes the results back to standard output. The format
28 of these messages is described below.
29
30
31 The daemon processes requests interleaved which allows to
32 send ICMP messages to a large number of hosts efficiently.
33 Parameters like the minimum delay between ICMP messages or
34 the maximum number of ICMP messages on the wire can be used
35 to control the network load created by this
36 daemon.
37
38
39 The __nmicmpd__ daemon is usually used by the Tnm(n) Tcl
40 extension which starts the daemon automatically when needed.
41 However, you may also choose to run this daemon under the
42 control of inetd(8). This allows remote sites to send ICMP
43 messages from your machine.
44 !!PROTOCOL
45
46
47 The protocol used to access the nmicmpd is a simple
48 request/response protocol. Note that requests are not
49 necessarily processed in the order they are received by the
50 nmicmpd. The request message format is as
51 follows:
52
53
54 0 7 8 15 16 23 24 32
55 +--------+--------+--------+--------+
56 | version| type | status | flags |
57 +--------+--------+--------+--------+
58 | transaction identifier |
59 +--------+--------+--------+--------+
60 | IPv4 address of the ICMP target |
61 +--------+--------+--------+--------+
62 | ttl | timeout| retries| delay |
63 +--------+--------+--------+--------+
64 | size | window |
65 +--------+--------+--------+--------+
66
67
68 The response message format uses the same header. The
69 response value is encoded in the IPv4 address field and the
70 value field. Note that the meaning of the value field
71 depends on the type of the ICMP
72 request/response.
73
74
75 0 7 8 15 16 23 24 32
76 +--------+--------+--------+--------+
77 | version| type | status | unused |
78 +--------+--------+--------+--------+
79 | transaction identifier |
80 +--------+--------+--------+--------+
81 | IPv4 address of responding host |
82 +--------+--------+--------+--------+
83 | value |
84 +--------+--------+--------+--------+
85
86
87 The value of the version field is 0x00. The type field
88 indicates the requested ICMP operation. The values defined
89 for this initial version are:
90
91
92 0x01 ICMP echo request
93
94
95 0x02 ICMP mask request
96
97
98 0x03 ICMP timestamp request
99
100
101 0x04 ICMP trace request
102
103
104 The status field indicates that return status of the
105 requested operation. This field is zero for all request
106 messages. Response messages may use the following values to
107 indicate if there have been errors while processing this
108 request.
109
110
111 0x00 NOERROR
112
113
114 0x01 TIMEOUT
115
116
117 0x02 GENERROR
118
119
120 The flags field is used to signal special conditions. The
121 only defined bit is the FINALHOP bit (0x01) which may be set
122 in responses to a ICMP trace request message. It indicates
123 that a trace request reached the destination
124 host.
125
126
127 The transaction identifier is used to identify a request and
128 is returned unchanged in the response packet. The IPv4
129 address in a request message defines the address of the
130 target host. The IPv4 address in the response message
131 indicates the IP address of the host which actually answered
132 the request.
133
134
135 The ttl value is used by ICMP trace requests to set the IP
136 TTL option field. The timeout value is given in seconds
137 while the delay value is given in milliseconds. The retries
138 value defines the number of retries to perform the requested
139 ICMP operation. A value of 0 indicates that no retries are
140 made. The size parameter specifies the size of the ICMP
141 packet. Note that the ICMP server might choose a different
142 size if required by the ICMP protocol. The window parameter
143 defines how many ICMP packets may be send in parallel to
144 limit the number of ICMP packets on the wire.
145 !!SEE ALSO
146
147
148 scotty(1), tkined(1), Tnm(n)
149 !!AUTHORS
150
151
152 Erik Schoenfelder
153 Juergen Schoenwaelder
154 ----
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