![]() #pcap filter expr " port 80 and (tcp & 0xf0) > 2):4] = 0x47455420 or tcp & 0xf0) > 2)+8:4] = 0x20323030)"Īlternatively, in the UI go to Maintenance > Service Information > Packet Captures and enter just the filter you want into the filter section (quotation marks are not needed). Two protocols on top of IP have ports TCP and UDP. To use this on a ProxySG, either enter the command line entry as follows (take note to use quotation marks): You can also add things like DNS by adding another port: You could specify "304" or "500" by determining what the hex values for those items is. Instead of "GET " you could use the hex values for "HEAD" or "POST". The values can be changed by replacing with the data you want. By using the filter above, you can gather only GETs with valid, new content responses. This filter is very powerful on a very busy ProxySG, as sometimes there is enough data traversing the proxy to only capture a few seconds before hitting the 100 MB limit. A typical HTTP response will start with "HTTP/1.1 200 OK". ![]() The third bullet is offset by 8 bytes and is for an HTTP response. ![]() wireshark other options -Y display filter expression. The second bullet restated says "TCP offset 47455420" which is literally "GET " (G, E, T, space) wireshark-filter - Wireshark display filter syntax and reference. Most common for a transparent HTTP environment. The first part is to only capture TCP or UDP port 80. For example, to capture only packets sent to port 80, use: dst tcp port 80 Couple that with an http display filter, or use: tcp.dstport 80 & http For more on capture filters, read 'Filtering while capturing' from the Wireshark user guide, the capture filters page on the Wireshark wiki, or pcap-filter (7) man page. You can filter on just about any field of any protocol, even down to the HEX values in a data stream. The following information is taken in part from the Wireshark Wiki page on capturing HTTP GET requests ( /CaptureFilters). The filtering capabilities of Wireshark are very comprehensive.
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