We requests that your routers be configurable, at the interface level, to prevent the forwarding of an ICMP echo-request packet through an interface that has a broadcast or wire address that matches the destination address of that packet.

Modifications that cause the forwarding path to behave differently for some type of packets are *bad*. ICMP echo-requests should be treated identically to other sorts of packets. If you s/an ICMP echo-request/an IP/, then you have the same as "no ip directed-broadcast". Your wording is sufficiently vague such that I can't tell if that's what you meant or not. I don't know if you're trying to avoid being cisco-specific, or if you're being vague for some other reason.

We also request that the default configurations of your routers be modified to prevent said forwarding.

I don't have a problem with this.

We request that your routers be configurable, both globally and and the interface level, with the interface configuration overiding the global configuration, to prevent the forwarding of an IP packet with a source network address different from the network address of the interface on which it was received. We also request that the default configurations of your routers be modified to prevent, globally, said forwarding.

I'd be concerned that having this as a default is not necessarily the right thing in sufficiently large numbers of situations as to make this a bad idea. --jhawk

On Sat, 25 Apr 1998, Rusty Zickefoose wrote: ==> So, if someone, or possibly a group of someones, were to make the ==>following request to the various router vendors, would they be met with ==>approval by most of the readers? ==> ==> We requests that your routers be configurable, at the interface ==>level, to prevent the forwarding of an ICMP echo-request packet through an ==>interface that has a broadcast or wire address that matches the ==>destination address of that packet. We also request that the default ==>configurations of your routers be modified to prevent said forwarding. This is against RFC 1812. RFC 1812, "Requirements for IP Version 4 Routers", Section 5.3.5, specifies: --- A router MAY have an option to disable receiving network-prefix- directed broadcasts on an interface and MUST have an option to disable forwarding network-prefix-directed broadcasts. These options MUST default to permit receiving and forwarding network-prefix- directed broadcasts. --- Someone has stated before that editor(s) of said RFC are aware of this and have discussed the change in default. Note that I'm not arguing that it *should* be the default, I'm just arguing that vendors have implemented it this way because that's the way they were told to in the RFC. If after reading http://www.quadrunner.com/~chuegen/smurf.txt, you think that I believe directed-broadcasts should be on by default, go back and read agian. =) Now, since this has been beaten past the jelly stage, can we please put the topic to sleep? Thank you. /cah