06-13-2011
ARP filter/netfilter
Your problem is that ARP is not an IP protocol, it is a layer below IP. The ethertype is not ip, and as a result, the packets never get into the netfilter hooks. arp is processed by the kernel without the ip layer.
Recent kernels have a config option ARPD that allows for substitution of a daemon for the kernel's arp resolution. That should enable you to do whatever you want to the arp packets.
There is also a BRIDGE_NETFILTER option that enables mac layer firewalls. By creating a virtual device in a bridge configuration you should be able to get those pesky arp packets into the netfilter framework.
9 More Discussions You Might Find Interesting
1. Programming
Hi everybody,
I have to write a module for matching in netfilter , extending the netfilter but I'm facing some problems can somebody guide me in that. I know that I need to write matching module working in kernel space and a program in userspace. I went through the HOWTO on netfilter-hacking but... (0 Replies)
Discussion started by: Trusted Penguin
0 Replies
2. Programming
Friends I'm facing a big problem trying to extend the netfilter. Somone please help me with your quick reply (any hint) as I've to meet a deadline.
My problem is that I've written a new netfilter target module and its corresponding userspace program for iptables to change the packet type of a... (0 Replies)
Discussion started by: Rakesh Ranjan
0 Replies
3. Programming
Hello friends i'm trying to extend iptables to include a target by which we can change the packet type field of a packet.
For this i created a kernel module and a userspace extension.
Now i face the problem that when i try to invoke iptable with the target i created i get an error message saying... (1 Reply)
Discussion started by: Rakesh Ranjan
1 Replies
4. IP Networking
hi,
i'm using tcpreplay to send a traffic trace to my wireless interface (the trace is been captured by the same interface). It seems as netfilter can't trace connections. Is it possible? (0 Replies)
Discussion started by: littleboyblu
0 Replies
5. Cybersecurity
Hi everyone, I would like to allow multi users to access P2P networks, so I wonder if there's a way to tracking these kind of protocols with netfilter, and also compatibility with nat, like the module conntrack_ftp seems to do with the FTP protocol.
Thanks guys. (0 Replies)
Discussion started by: nekkro-kvlt
0 Replies
6. Linux
HI,
Is the Netfilter and IPtables same?
Thanks & Regards
Arun (1 Reply)
Discussion started by: Arun.Kakarla
1 Replies
7. UNIX for Advanced & Expert Users
iam trying to built a firewall.so i have used netfilter for it.
in function main_hook sock_buff is returning null and in my log file continuously "sock buff null" is printed plse help to solve this problem..
(using print_string iam printing strings on current terminal (terminal we ping))
... (1 Reply)
Discussion started by: pavan6754
1 Replies
8. Cybersecurity
Hi all,
I would like to get some ideas and opinions on matter of libvirt netfilter application in KVM environment. I am looking for some easy way to control it with an API and possible experience with that and its performance in real life application.
Thanks for all ideas (0 Replies)
Discussion started by: smoofy
0 Replies
9. Cybersecurity
Hello,
on a PC with Debian 8 I try to use a Bash script with Netfilter rules so that only traffic goes in and out that is wanted. For that I set all 3 default policies to "drop". The machine uses DHCP to get its IP, gateway and DNS. And I never checked so I was quite surprised that my... (1 Reply)
Discussion started by: SInt
1 Replies
ARP(3) Library Functions Manual ARP(3)
NAME
arp - Internet Address Resolution Protocol
SYNOPSIS
bind -a #a /net/arp
/net/arp/ctl
/net/arp/data
/net/arp/stats
DESCRIPTION
The arp device provides the means by which the kernel resolves IP addresses into Ethernet addresses. A cache is maintained by the arp
device to speed the process.
The ctl file controls the ARP cache maintained by the kernel. The flush control message invalidates all entries in the cache. The delete
ipaddr control message invalidates a single cache entry. All IP addresses passed to the system are in the canonical textual form described
in ip(2). The perm ipaddr control message makes an existing cache entry permanent.
When the kernel boots, ipconfig sets up the IP stream and arpd opens #a/arp/data (see ipconfig(8)). This establishes the ARP cache and
enables arpd to receive all ARP packets from the network, which it uses to maintain the cache by writing the results of address resolution
requests back into the cache. The IP stream module uses the cache to translate IP addresses.
Subsequent opens of the data file allow the contents of the cache to be examined. Each cache entry consists of an IP address, an Ethernet
address, and the status of the entry. Entries may be invalid, permanent, or temporary. Permanent entries will never be aged from the
cache. Temporary entries may be replaced by new addresses entered by the ARP server.
The file stats reports the cache performance.
SEE ALSO
ip(3), ipconfig(8)
SOURCE
/sys/src/9/port/devarp.c
ARP(3)