Filter
Top Products
ICMP Overview window 204
Models 2616RC, 3096RC & 3196RC Admin Reference Guide 12 • IP (IP, TCP, UDP, & ICMP)
configuration is to block the ICMP redirect messages because in some instances they could alter the routing
table with undesirable effects, which is considered a breach of security.
The options are:
• allowRedirects(0)
• stopRedirects(1)
After making your selection, click the Modify button to apply the changes.
ICMP Statistics
The ICMP Statistics section of the ICMP Overview window (see figure 115 on page 203) displays the ICMP
message counters. ICMP messages are displayed in the window table as columns comprising two types
of messages:
• Messages received by the T-DAC (InMibVariable)
• Messages sent by the T-DAC (OutMibVariable)
The numbers following the parameters can be a good source of what is happening on the network to point out
potential problems. Both gateways (routers) and hosts can send ICMP messages.
Total ICMP Datagrams Received (icmpInMsgs)
The total number of ICMP messages which the T-DAC has received.
Note
This counter includes all those counted by icmpInErrors (see “w/
Errors (icmpInErrors, icmpOutErrors)”).
Total ICMP Datagrams Sent (imcpOutMsgs)
Similar to icmpInMsgs, Total Sent represents the total number of ICMP messages which the T-DAC has
attempted to send. This variable includes all ICMP messages counted by icmpOutErrors (see “w/Errors (icmp-
InErrors, icmpOutErrors)”).
w/Errors (icmpInErrors, icmpOutErrors)
The number of ICMP messages which the T-DAC received/sent but having ICMP-specific errors (for example,
bad ICMP checksums, bad length, or non-routable errors).
Destinations Unreachable (IcmpInDestUnreachs, IcmpOutDestUnreachs)
The number of ICMP destination unreachable messages received/sent. For instance, if the information in a
gateway’s routing table determines that the network specified in a packet is unreachable, the gateway will send
back an ICMP message stating that the network is unreachable. The following conditions will send back an
unreachable message:
• The network is unreachable
• The host is unreachable
• The protocol is not available to the network