My home server has two main interfaces, A C program to reflect an IP packet back to the source - faddy/reflector. Whenever an attacker sends a packet to victim, the packet is intercepted by the reflector application and re-sent as a packet from relayer to the attacker's host. The reply that is sent by the attacker's host to relayer is then sent back as a packet from victim (in. What is a TCP/IP Packet? In its simplest form, a packet is the basic unit of information in network transmission. Most networks use TCP/IP as the network protocol, or set of rules for communication between devices, and the rules of TCP/IP require information to be split into packets that contain both a segment of data to be transferred and the address where the data is to be sent. I can easily mark matched packets: Now, I'd like to put some rule in the POSTROUTING chain (probably of the mangle table) to match packets marked with 11 and send them to I found the ROUTE target, but that seems to only re-write the source interface (unless I'm reading it incorrectly). Is iptables capable of this? Do I have to mess around with the routing table (via Edit: I thought that maybe I should provide more information. I have no other iptables rules at present (although I may create some rules to carry out unrelated tasks in the future). Also, the output of I haven't touched the routing table - this is just how it is at present (although it looks fairly dirty). I'm sorry, but I don't have the legacy And the output of Edit: I've gotten something sorta working, but it's not forwarding marked packets to tun0. Basically, I added a table (11), and used: When I just Running EDIT: I've spent a long time on this, and although it still doesn't work, I think I'm a bit closer. The iptables rule has to be in the I've spent 5 hours on this now, so I'm taking a break and will probably return to it later tonight or sometime tomorrow.
Ethan
EthanEthan
4 AnswersI've recently hit a similar issue, albeit a slightly different. I wanted to route only TCP port 25 (SMTP) over an OpenVPN tap0 interface, while routing all other traffic (even for the same host) over the default interface. To do so, I had to mark packets and set up rules for handling it. First, add a rule that make the kernel route packets marked with You could have added a symbolic name to Add a route for redirecting traffic over a different interface, assuming the gateway being Very important! Flush your routing cache, otherwise you will not get a response back and sit with your hands in your hair for some hours: Now, set a firewall rule for marking designated packets: The above rule applies only if the packets come from the local machine. See http://inai.de/images/nf-packet-flow.png. Adjust it to your requirements. Generic-eng2.2 froyo ver 1.5.7-20111124.115437. For instance, if you only want to route outgoing HTTP traffic over the To prevent the packets sent over Finally, relax the reverse path source validation. Some suggest you to set it to
LekensteynLekensteyn
I solved this. The issue was with the routing rules in table 11. Table 11 was getting hit, but the routing rules make it inoperable. This script is what I now use, and it seems to work well (although it's obviously specific to my setup). Also, I created a new table 21 devoted to the main uplink (eth1). ## MeanderingCode edit (because I can't comment, yet) Thanks for this answer! It seems as though this could get messy, as you would have to maintain route info here (possibly duplicating, or breaking other things which may want to set routes. You may be experiencing 'weird things' in your routing table from OpenVPN because the server is configured to 'push' routes, enabling all traffic to route through the VPN network interface, rather than the 'bare' internet. Or your OpenVPN config or whatever script/application sets it up is setting routes. In the former case, you can edit your OpenVPN configuration and put in a line containing 'route-nopull' Cheers!
EthanEthan
I think you want: But I haven't tested the above.
mfarvermfarver
This can be done without iptables command Execute simple ip command For uid 1002: Add default route for table 502 over interface that you want say
jainendrajainendra
Not the answer you're looking for? Browse other questions tagged iptablesrouting or ask your own question.I've got a pair of hosts with very bad routing between the two, but I have a third host that has very good ping to each. To work around the bad routing, I'm setting up the third host to bounce packets back and forth between the two. This third host has an IP address that isn't used for anything else. My ideal configuration would be, when host 1 sends a packet to host 3, host 3 automatically NATs the source and destination addresses, replacing source=host3 and destination=host2, then forwards the packet. The inverse should be true: If host2 tries to respond, the packet should go back to host3, which will NAT it back to source=host3, destination=host1. No connection tracking is required -- this can be done entirely statelessly. Where I'm stuck is in getting both DNAT and SNAT to work at the same time. It seems like, if a packet is handled by DNAT, it's automatically marked to skip the SNAT rules: the DNAT works fine, but the source address isn't getting translated. What is the proper iptables configuration to achieve this? The Best Analog Delay Pedals. We’ve covered the difference between analog and digital delay in more depth elsewhere in the article, but in case you’re not into reading a ton of technical jargon: analog delay sounds more natural while digital is more accurate.If you favor an organic tone over to-the-millisecond accuracy, definitely consider one of the pedals below. Find great deals on eBay for analog delay. Shop with confidence. Vintage analog delay analog delay rack analog delay pedal aqua puss tape delay mxr carbon copy delay pedal stereo analog delay analog reverb analog chorus analog. New Listing Twinote BBD DELAY Analog Delay Pedal For Electric Guitar Ultra Short Delay Time. Analog delay times vary. Digital delay does its thing, in basic terms, by splitting the signal at the input, running one path through an analog-to-digital (A/D) converter, sampling it, and blending it back with the dry signal at a desired delay time after translating it back through a digital-to-analog (D/A) converter. Getting the Most Our of Your Delay Pedal. A column that can help demystify delay newbs while teaching old dawgs a few tricks. Of course these numbers are ballpark figures and will vary from unit to unit. Digital delays produce a clear pristine sound and are generally deployed for longer times, while analog units have a warmer, more lo. Analog delay lines have clock dividers so that only a single-phase clock input is needed. We'll discuss specific IC's later in this article. 1-AN ANALOG DELAY LINE is composed of a bucket-brigade delay line, input and output lowpass filters, and a two-phase clock (a). The circuit produces a time-delayed replica of the input signal (b).
CFSworksCFSworks
1 AnswerThe strange behavior was due to CONNTRACK. SNAT and DNAT indeed work fine together if nothing else gets in the way. Also, I've only configured the SNAT and DNAT in one direction. Because there is traffic constantly going through, SNAT and DNAT's automatic reverse translation take care of the return path for me.
CFSworksCFSworks
Not the answer you're looking for? Browse other questions tagged linuxiptablesipforwarding or ask your own question.
0 Comments
Leave a Reply. |