3Com 4007, Command Reference Manual

Page: 238 / 574

238 C
HAPTER
12: I
NTERNET
P
ROTOCOL
(IP)
ip interface
Layer 2
Switching
Modules
✓
Multilayer
Switching
Modules
icmpRedirect
Enables or disables the transmission of an Internet Control Message
Protocol (ICMP) redirect to the sender of a frame. An ICMP redirect
indicates that there is a better gateway available to handle the frame than
this routing interface.
Valid Minimum Abbreviation
ip i icmpre
Important Considerations
■
The software determines whether there is a better path for the frame
by determining whether the source interface is the same as the
destination interface and whether the frame’s sender is on a directly
connected network. If the software determines that a received frame
has a better path available through another gateway:
■
It sends an ICMP redirect message back to the originator of the
frame indicating the better gateway to use in the future
■
It routes the frame to the gateway
■
ICMP redirect can be set on a per-interface basis.
■
For better performance or if you have applications that ignore ICMP
redirects, disable the ability of the interface to send ICMP redirects.
■
If you have two interfaces that belong to virtual LANs (VLANs) that
share a given port and you want to completely disable ICMP redirects
for that port, disable the redirects for each interface that shares that
port. If you disable it for only one interface and enable it for the other,
you may not get the performance improvement that you want.