hardening sys.ctl - one question

[Gen2ly]

I've been looking to add a little bit of security to my laptop and I'm using an example that looks repetative:

# Disables IP source routing
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.lo.accept_source_route = 0
net.ipv4.conf.eth0.accept_source_route = 0
net.ipv4.conf.default.accept_source_route = 0

# Enable IP spoofing protection, turn on source route verification
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.lo.rp_filter = 1
net.ipv4.conf.eth0.rp_filter = 1
net.ipv4.conf.default.rp_filter = 1

# Disable ICMP Redirect Acceptance
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.lo.accept_redirects = 0
net.ipv4.conf.eth0.accept_redirects = 0
net.ipv4.conf.default.accept_redirects = 0

Are these values repetative or do I need them all?

[Kinstonian]

IP source routing is an IP option where the source can determine the routers the traffic will take to get to its destination. I think it's pretty much irrelevant now since it's so common for routers to drop IP source routed packets.

The "Enable IP spoofing protection, turn on source route verification" is I believe reverse path filtering, which can be explained here (http://en.wikipedia.org/wiki/Reverse_path_forwarding)

The "Disable ICMP Redirect Acceptance" should probably be enabled to prevent someone from using ICMP redirect packets to tell your computer to send its traffic to a different router.

[Gen2ly]

good to know more about what the values mean. i just wondering if are all these values necessary though? I've seen a couple of examples where just "all" was used.