Socket Filter on a NIC?

Link to this post 29 Mar 11

Hi Guys,

I am trying to find out if the Kernel does/can put a filter on a NIC?

The thread i am trying to follow, is that i have a small theory that the filter may only allow packets who's Destination MAC match the MAC of the NIC they are trying to cross.



Link to this post 30 Mar 11

Are you asking whether or not the Linux kernel can filter network packages based on MAC addresses? In that case, the answer is yes, it can. The kernel can also be configured to block attempts at spoofing local addresses. Note that on most (if not all) distributions, none of these are enabled by default.

If this didn't answer your question, please expand upon what you're trying to figure out ;)

Link to this post 30 Mar 11

Hey Jabirali,

Yes i am aware that the Linux Kernel can filter packets based on MAC. I have seen that ipatbles is capable of doing this via Source MAC.
I have just ventured through many pages ;) (including yours) to get a better understanding of the Proc settings that facilitate switching on/off the 'other' networking settings such as "rp_filter", "log_martians", "accept_source_route", .... and it does not look like i need any of these.

What i am trying to do is quite difficult, and im still learning Linux :), but i was asking a specific question to see if i could understand more about what my NIC would be doing....

Instead of re-writing everything, i will post a link instead ---->


Link to this post 31 Mar 11

I have gone through all of these settings (in Image) and i think that i have tuned them appropriately (Some are automatically set).

I found that the ones labelled as redirect refer to ICMP (ping) and would not effect my TCP packets, is this correct?
Is it also correct that the ones that would affect routing of my packets are: rp_filter, arp_filter, arp_ignore, proxy_arp, accept_source_route, forwarding?

FYI - I coloured everything Yellow that has a value other than Zero.

Link to this post 02 Apr 11

In networking, anything being redirected effects your packets, because your packets are whats being redirected. Every bit of data transmitting through any network are in forms of packets.

Yes what you listed above will effect the routing of your packets.

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