IP filtering is a mechanism that allows the user to apply actions to a specific flow identified by a flow key from the data ports to the CPU. (IP and MAC) depending on the rules you wish to create. For example, create an IP list called mylist, run: switch (config) # ipv4 access-list my-list. Wireshark Filter by IP. Ip.addr 10.43.54.65. In plain English this filter reads, “Pass all traffic containing an IP Address equal to 10.43.54.65.” This will match on both source and destination. You can read more about this in our article “How to Filter by IP in Wireshark” Wireshark Filter by Destination IP. Server Load Balancer Hardware & Software.
An IP filter is used to filter inbound or outbound IP traffic. It resides within the IP protocol stack, as shown in Figure 5-1. For inbound traffic, it is called after an IP packet has been reassembled. For outbound traffic, it is called just prior to IP fragmentation. If IPSec processing is required for a given packet, the filter is called twice—immediately before and after any IPSec processing.
The Anatomy of an IP Filter
There are two basic categories of IP filters: IPv4 filters and IPv6 filters. With the exception of their handling of addresses, they are essentially equivalent. The same basic data structure, ipf_filter, is used to describe both.
The data structure contains five fields: cookie, name, ipf_input, ipf_output, and ipf_detach.
The first field, cookie, can contain arbitrary data. Your KEXT assigns it a value when it attaches the filter to the IP stack. The IP stack then passes that value as an argument whenever the networking stack calls any function in your KEXT. This allows a single filter to have multiple behaviors depending on where it is attached by testing values stored in the cookie.
The structure referenced by this field can be arbitrarily defined by your KEXT. As far as the kernel is concerned, it is essentially a void pointer. This mechanism is commonly used to store information about memory allocations associated with a particular filter instance.
The second field, name, is the name of your filter. This is used only for debugging purposes, but should always be filled in. It should contain either the identifier for the KEXT or something similar, for ease of identification.
The remaining fields, ipf_input, ipf_output, and ipf_detach, are pointers to callback functions in your KEXT. Those callbacks are called whenever your filter is asked to handle inbound packets, handle outbound packets, or detach, respectively.
The ipf_input, ipf_output, and ipf_detach function pointers are described in their data type declarations—respectively, ipf_input_func, ipf_output_func, and ipf_detach_func.
Generally, your ipf_input_func callback will be called as soon as a packet has been identified as being a IP packet and reassembled. Similarly, your ipf_output_func function will be called just prior to sending it to the data link interface layer (where it may be further processed by interface filters). However, in some cases, such as IPSec encapsulation, your IP filter will be called once as each layer of encapsulation is decoded.
A registered filter is identified by the opaque type ipfilter_t. This is used later when you unregister the filter.
IP Filter Gotchas
There are several quirks specific to modifying traffic in an IP filter. Some of these include:
If your filter modifies the protocol of inbound traffic or the destination of outbound traffic, the packet may be misdelivered as a result of caching in the IP stack.
To prevent this problem, your filter must use ipf_inject_input or ipf_inject_output, as appropriate. Your ipf_input_func or ipf_output_func callback should then swallow the previous version by returning EJUSTRETURN.
Ip Filters For Mac Osx
IP filters only receive reassembled packets. It is not possible to filter on packet fragments.
It is possible to create filter loops in which one filter changes a value and reinjects the packet, which causes a second filter to change the value back and reinject it in an endless loop.
To reduce the likelihood of such a loop, when reinjecting packets, your filter should always specify itself as the filter_refparameter.
Copyright © 2003, 2012 Apple Inc. All Rights Reserved. Terms of Use | Privacy Policy | Updated: 2012-01-09
uTorrent IPFilter Updater – To keep the list of blocked IP addresses up-to-date.
IP Filter lists for uTorrent from a selected mirror, developed by David Moore.
Ip Filters For Macbook
IPFilter Updater
IP Filter lists for use in Bit Torrent clients.
Ip Filter For Mac
Features
- Provides choice of list providers.
- Automatically decompresses lists that are in Gzip or Zip format.
- Can automatically schedule itself to update the list silently.
- Auto-updating.
Requirements
- Microsoft Windows XP+
- .NET Framework 4 or greater
Ip Filter List
Improvements
- For troubleshooting, a basic log is written to ipfilter.log
- Downloaded list(s) are now sorted and merged to make the list smaller, more compact and faster to load by P2P clients
- Applications receive their own copy of the ipfilter.dat, formatted to each application’s preferred format
Changes
- Now installing to AppDataLocalProgramsIPFilter (instead of AppDataLocalIPFilter) to follow the established convention for per-user applications
- The cached ipfilter.dat will now be stored in AppDataLocalProgramsIPFilteripfilter.dat
What is IPFilter Updater?
It’s a small Windows application that will download and update an ipfilter list for use in Bit Torrent clients.
What Bit Torrent clients are supported?
Currently uTorrent, BitTorrent and qBittorrent are supported out of the box, but you can also configure other applications to pick up the downloaded list.
What is an ipfilter?
An ipfilter list is a simple (but usually very large) list of addresses and ranges of malicious peers that will transmit junk data (i.e. anti-P2P) or peers that may be intrusive on your net privacy.
Why do I need an ipfilter?
For privacy and more reliable peers
Why do I need IPFilter Updater?
It will make it easier to download a list, and keep it up to date
Where does the list come from?
Developer said that, he is not maintain any of the lists and try to keep a variety of third party list options available, but the availability and quality of free, up to date lists seems to be dwindling.
Where does the filter get downloaded to?
The ipfilter.dat is downloaded to your local user profile in a directory called IPFilter i.e. %LocalAppData%IPFilteripfilter.dat
For example, if your username is Bob and you were on Windows 7 or higher, then the location by default would resolve to C:UsersBobAppDataLocalIPFilteripfilter.dat
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