Re: ICMP Well-Known Port

[Joseph S D Yao <jsdy () cospo osis gov>]

> Evidently I'm really missing the boat.  I've been trying to find the
> well-known port for ICMP.  Is there no such thing?
>
> Dean C. Rowan
> Whittier Public Library

ICMP is at a lower level than TCP "well known ports".  It is another
protocol, on a par with TCP or UDP.

IP packets can be "raw IP" or TCP or UDP or ICMP or ...  Cf.
/etc/protocols:
=======================================================================
# Internet (IP) protocols
#
ip      0       IP              # internet protocol, pseudo protocol number
icmp    1       ICMP            # internet control message protocol
ggp     3       GGP             # gateway-gateway protocol
tcp     6       TCP             # transmission control protocol
egp     8       EGP             # exterior gateway protocol
pup     12      PUP             # PARC universal packet protocol
udp     17      UDP             # user datagram protocol
hmp     20      HMP             # host monitoring protocol
xns-idp 22      XNS-IDP         # Xerox NS IDP
rdp     27      RDP             # "reliable datagram" protocol
=======================================================================

The "well known ports", OTOH, are partly defined in /etc/services:
=======================================================================
echo           7/tcp                 # Echo
echo           7/udp                 #
discard        9/tcp  sink null      # Discard
discard        9/udp  sink null      #
systat        11/tcp  users          # Active Users
daytime       13/tcp                 # Daytime
daytime       13/udp                 #
qotd          17/tcp  quote          # Quote of the Day
chargen       19/tcp  ttytst source  # Character Generator
chargen       19/udp  ttytst source  #
...
=======================================================================

--
Joe Yao                         jsdy () cospo osis gov - Joseph S. D. Yao
COSPO/OSIS Computer Support                                     EMT-B
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