Measuring bandwidth on Checkpoint Gaia

Intro
Sometimes you don’t have the tools you want but you have enough to make do. Such is the case with the command line utilities of the CLI of Checkpoint Gaia. It’s like a basic Linux. The company I consult for is beginning to hit some bandwidth limits and I wanted to understand overall traffic flow better. In the absence of any proper bandwidth monitors I used the netstat command and some approximations. Crude thouigh it may be it already gave me a much better idea about my traffic than I had going into this project.

The details
I call this BASH script netstats.sh

#!/bin/bash
# for Gaia, not IPSO
c=0
while /bin/true; do
  v[1]=`netstat -Ieth1-01 -e|grep RX|grep TX`
  n[1]="vlan 102           "
  v[2]=`netstat -Ieth1-05 -e|grep RX|grep TX`
  n[2]="vlan 103 200.78.39    "
  v[3]=`netstat -Ieth1-02 -e|grep RX|grep TX`
  n[3]="vlan 103 10.31.42"
  v[4]=`netstat -Ieth1-03 -e|grep RX|grep TX`
  n[4]="trunk for VPN      "
# interesting line:
#           RX bytes:4785585828883 (4.3 TiB)  TX bytes:7150474860130 (6.5 TiB)
  date
  for i in {1..4}; do
    RX=`echo ${v[$i]}|cut -d: -f2|awk '{print $1}'`
    TX=`echo ${v[$i]}|cut -d: -f3|awk '{print $1}'`
#    echo "vlan ${n[$i]}        RX,TX: $RX, $TX"
    if [ $c -gt 0 ]; then
      RXdiff=`expr $RX - ${RXold[$i]}`
      TXdiff=`expr $TX - ${TXold[$i]}`
# observed scaling factor: 8.1 bits/byte
      RXrate=$(($RXdiff*81/100000000))
      TXrate=$(($TXdiff*81/100000000))
      echo "${n[$i]}    RX,TX: $RXrate, $TXrate Mbps"
    fi
# old values
    RXold[$i]=$RX
    TXold[$i]=$TX
  done
  c=$(( $c + 1 ))
  sleep 10
done

It’s pretty self-explanatory. I would just note that in the older IPSO OS you don’t have the ability to get the bytes transferred from netstat. Just the number of packets, which is an inherently cruder measure. The calibration of 8.1 bits per byte (there is overhead from the frames) is maybe a little crude but it’s what I measured over the source of a couple minutes.

A quick glance at Redhat or CentOS shows me that this same script, with appropriate modifications for the interface names (eth0, eth1, etc), would also work on those OSes.

IPSO
I really, really wanted some kind of measure for IPSO as well. So I tackled that as best I could. Here is that script:

#!/bin/bash
# for IPSO, not Gaia
c=0
while [ 1 -gt 0 ]; do
# eth1-01: vlan 802; eth1-05: vlan 803 (144.29); eth1-02: vlan 803 (10.201.145)
  v[1]=`netstat -Ieth-s4p1|tail -1`
  n[1]="vlan 208.129.99     "
  v[2]=`netstat -Ieth-s4p2|tail -1`
  n[2]="vlan 208.156.254     "
  v[3]=`netstat -Ieth-s4p3|tail -1`
  n[3]="vlan 208.149.129     "
  v[4]=`netstat -Ieth-s4p4|tail -1`
  n[4]="trunk for Cisco and b2b"
# interesting line:
#Name         Mtu   Network     Address             Ipkts Ierrs    Opkts Oerrs  Coll
#eth-s4p1     16018 <Link>      0:a0:8e:c4:ff:f4 72780201     0 56423000     0     0
  date
  for i in {1..4}; do
    RX=`echo ${v[$i]}|awk '{print $5}'`
    TX=`echo ${v[$i]}|awk '{print $7}'`
#    echo "vlan ${n[$i]}        RX,TX: $RX, $TX"
    if [ $c -gt 0 ]; then
      RXdiff=$(($RX - ${RXold[$i]}))
      TXdiff=$(($TX - ${TXold[$i]}))
# observed: .0043 mbits/packet
      RXrate=$(($RXdiff*43/100000))
# observed: .0056 mbits/packet
      TXrate=$(($TXdiff*56/100000))
      echo "${n[$i]}    RX,TX: $RXrate, $TXrate Mbps"
    fi
# old values
    RXold[$i]=$RX
    TXold[$i]=$TX
  done
  c=$(( $c + 1 ))
  sleep 10
done

The conversion to bits is probably only accurate to +/- 25%, because it depends a lot on the application, i.e., VPN concentrator versus proxy server. I just averaged all applications together because that’s the best I could do. I compared it to a Cisco router’s statistics.

Conclusion
A script is provided which gives a measure of Mbps bandwidth usage by polling netstat periodically. It’s not exact, but even crude measures can help a network engineer.

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