1 Match by how many bytes or packets a connection (or one of the two 2 flows constituting the connection) has transferred so far, or by 3 average bytes per packet. 4 .PP 5 The counters are 64-bit and are thus not expected to overflow ;) 6 .PP 7 The primary use is to detect long-lived downloads and mark them to be 8 scheduled using a lower priority band in traffic control. 9 .PP 10 The transferred bytes per connection can also be viewed through 11 `conntrack \-L` and accessed via ctnetlink. 12 .PP 13 NOTE that for connections which have no accounting information, the match will 14 always return false. The "net.netfilter.nf_conntrack_acct" sysctl flag controls 15 whether \fBnew\fP connections will be byte/packet counted. Existing connection 16 flows will not be gaining/losing a/the accounting structure when be sysctl flag 17 is flipped. 18 .TP 19 [\fB!\fP] \fB\-\-connbytes\fP \fIfrom\fP[\fB:\fP\fIto\fP] 20 match packets from a connection whose packets/bytes/average packet 21 size is more than FROM and less than TO bytes/packets. if TO is 22 omitted only FROM check is done. "!" is used to match packets not 23 falling in the range. 24 .TP 25 \fB\-\-connbytes\-dir\fP {\fBoriginal\fP|\fBreply\fP|\fBboth\fP} 26 which packets to consider 27 .TP 28 \fB\-\-connbytes\-mode\fP {\fBpackets\fP|\fBbytes\fP|\fBavgpkt\fP} 29 whether to check the amount of packets, number of bytes transferred or 30 the average size (in bytes) of all packets received so far. Note that 31 when "both" is used together with "avgpkt", and data is going (mainly) 32 only in one direction (for example HTTP), the average packet size will 33 be about half of the actual data packets. 34 .TP 35 Example: 36 iptables .. \-m connbytes \-\-connbytes 10000:100000 \-\-connbytes\-dir both \-\-connbytes\-mode bytes ... 37
