We've replaced the original http dissector in the dissector table, Local f_resp_code = Field.new("")įunction http_wrapper_proto.dissector(tvbuffer, pinfo, treeitem) so we can check for them later in the dissector. request method or HTTP response code, so declare those here HTTP frames that contain a header usually include the HTTP Http_wrapper_len = ProtoField.uint32("http.hdr_len", "Header length (bytes)") Local http_wrapper_proto = Proto("http_extra", "Extra analysis of the HTTP protocol") Post-up tcpdump -i eth0 host 192.168.111.1 -w '/home/doug/eth0-%F-%H-%M-%S.This can be achieved simply with a Lua dissector that adds an HTTP header field to the packet tree, allowing you to filter for it, as shown in this screenshot:Ĭopy this Lua script into your plugins directory (e.g., $/plugins/1.4.6/http_a), and restart Wireshark (if already running). Second, the post-up method, here is the /etc/network/interfaces file: # interfaces(5) file used by ifup(8) and ifdown(8) First, the delay method the below line is added to /etc/rc.local: sleep 20 tcpdump -i eth0 host 192.168.111.1 -w '/home/doug/eth0-%F-%H-%M-%S.bin' -G 600 & So consider adding a delay, or adding it as a post-up addition to the /etc/network/interfaces file. Now, to automate starting this command on boot, you could add it to /etc/rc.local, as mentioned in the comments, however that might be prone to a race condition between rc.local and the interface not being up in time, resulting in the following entry in /var/log/syslog (where it did not work 1 out of 3 times): Apr 22 12:06:45 desk-ss rc.local: tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytesĪpr 22 13:30:47 desk-ss rc.local: tcpdump: eth0: That device is not upĪpr 22 13:33:20 desk-ss rc.local: tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes See the tcpdump man page for more details. I would open wireshark and use file then open and open the appropriate file based on the log entry timestamp.Īlternatively, you could use the -C option instead of -G to rotate the output files based on file size instead of by time. Now, say I had an interesting /var/log/kern.log entry, that I wanted to investigate in detail at the packet level. To prevent huge files, and to make later investigation easier, the file name is changed every 10 minutes, with the file name containing the date and time as an identifier. Will capture all traffic to/from 192.168.111.190 and save the entire packet to a file. You can still use wireshark to view the packets in detail later on.įor example (where I am using a local IP address, just for the example): sudo tcpdump -i eth0 host 192.168.111.190 -w 'eth0-%F-%H-%M-%S.bin' -G 600 The suggestion is to use tcpdump to do the actual packet capturing and saving. OS Information: Description: Ubuntu 14.10 So is this how it should look, is a restart required, or any command to be executed? The current solution provided does not seem to be working, this is now the new contents of my /etc/network/interfaces file: # interfaces(5) file used by ifup(8) and ifdown(8) I know that such a thing, or at least something similar, could be done, but I just do not know the technical detail of exactly how I would get it to work, so that is really why I am asking about it here.Įven if I would not be able to get it to startup in the background on startup and start doing this by itself without launching any GUI, at least a way so that I could get it to filter and automatically save specific packets would be good (even if I would need to manually start Wireshark). It would also then be very useful for it to save the captured packets automatically that match these specifications to a directory that I would specify. I have got Wireshark installed and I am wanting to monitor the traffic to and from a specific IP address, so what would be really useful would be if I could get Wireshark to start by itself on startup and then start capturing packets on eth0 which are either from or to that specific IP address.
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