I am looking to find the traffic through a specific port for a time frame. For example, traffic through 3306 port for 10 seconds. Is there a way to find this information?
I see that "/sbin/ifconfig eth0 05" can be used to get information on total bytes but I am looking to find information about specific port's traffic.
Thanks in advance,
tcpdump -i eth0 -s 1500 port 3306
sudo iftop -P -n -N -m 10M -f 'port 3260'
-P display ports
-n no hostname lookup
-N display ports not service names
-m limit for bandwidth scale
-f filter rule
Related
I am trying to capture the DHCP frames for analysis using the following command in my mac book.
sudo tshark -i en0 -f "port 67 or port 68" -a duration:300 -w /tmp/dump.pcap
I use the following command to get all the fields of all protocols in the packet but it is not printing any value. Is the capture filter option for the DHCP frame is correct? Any help is appreciated?
sudo tshark -T text -r /tmp/dump.pcap -V
Answer
Yes, your commands are OK. Maybe no DHCP packets arrived and therefore not captured. Try to force a DHCP activity by commands in second teminal window of the same device:
sudo dhclient -r
sudo dhclient
Warning: Do not apply these commands if you are connected remotely. First command releases the IP address and your connection will be interrupted without a possibility to put second command and get address back remotely.
Some details concerning data capture
The thsark filters have the same syntax as Wireshark.
Threre exist 2 (or 3) filter types:
capture filter, -f tshark option: It selects which packets will be captured and which not. This is useful e.g. for getting lower capture file size.
display filter, -Y tshark option: It selects which packets will be displayed from all captured ones.
You can combine both types.
Examples:
tshark -i eth0 -n -Y "ip.addr==8.8.8.8"
tshark -i eth0 -n -Y "ip.addr==8.8.8.8" -f "udp port 53"
tshark -i eth0 -n -Y "ip.addr==8.8.8.8 and udp.port==53"
All packets are captured, but only the 8.8.8.8 IP address packets are displayed.
Only the DNS packets are captured, and only the 8.8.8.8 IP address packets from captured are displayed.
All packets are captured, but only the 8.8.8.8 IP address packets having UDP port 53 (i.e. DNS) are displayed. Compare different syntax of the port filtering between the display and the capture filters in line above.
All other options like -a, -b, -w, -s can be applied too.
The tcpdump application is usefull too. It is available in most Linux systems even very small or special. It does not have a display filter option. Only capture filters can be applied. Other options are missing: -a, -b ...
sudo tcpdump -i eth0 -w /tmp/dhcp.pcap "udp port 67 or udp port 68"
I'm working on a project where my client is billed exorbitant rates for data transfer on a boat. When they are in port, they use 3g and when they are out at sea they use sattelite.
Every 30 minutes I need to check to see what network I am attached to (moving vessel) but I need to give them specific information on how much data is actually used to make these calls.
I was wondering if anyone knew of any way to get the exact bytes that were sent out and received via terminal response.
Right now I am running this command to get the IP address that my ISP has assigned me.
dig +short myip.opendns.com #resolver1.opendns.com
To identify which network is used right now you may check route table
netstat -r | grep default
You will see default interface used for connection.
There are multiple commands that will show you statistics for interface. E.g.
ip -s link show dev eth0
where eth0 interface identified from command above.
or
ethtool -S eth0
If you want to get data independently from interface(all data stats from boot) you may use IpExt sectoin of
netstat -s
All those metrics will provide system wide counters. For inspecting specific app you may use iptables stats. There are owner module in iptables-extensions that may help. Here are example commands:
# sudo su
# iptables -A OUTPUT -m owner --uid-owner 1000 -j CONNMARK --set-mark 1
# iptables -A INPUT -m connmark --mark 1
# iptables -A OUTPUT -m connmark --mark 1
# iptables -nvL | grep -e Chain -e "connmark match 0x1"
Iptables will allow you to clear counters whenever it needed. Also owner module allow you match packets associated with user group, process id and socket.
I am capturing network traffic by using tcpdump. The problem is: I can't see all capture data when the package is too long. For example, when the tcp frame length is more than 500, I just see 100-200 or less. How to display all frame data(500+)?
I have tried add -vv and -vvv parameter. This is my current command:
tcpdump -i eth1 tcp and host 10.27.13.14 and port 6973 -vv -X -c 1000
Add -s0 parameter:
tcpdump -i eth1 tcp and host 10.27.13.14 and port 6973 -s0 -vv -X -c 1000
I have been using wire-shark to analyse the packets of socket programs, Now i want to see the traffic of other hosts traffic, as i found that i need to use monitor mode that is only supported in Linux platform, so i tried but i couldn't capture any packets that is transferred in my network, listing as 0 packets captured.
Scenario:
I'm having a network consisting of 50+ hosts (all are powered by windows Except mine), my IP address is 192.168.1.10, when i initiate a communication between any 192.168.1.xx it showing the captured traffic.
But my requirement is to monitor the traffic of 192.168.1.21 b/w 192.168.1.22 from my host i,e. from 192.168.1.10.
1: is it possible to capture the traffic as i mentioned?
2: If it is possible then is wire-shark is right tool for it (or should i have to use differnt one)?
3: if it is not possible, then why?
Just adapt this a bit with your own filters and ips : (on local host)
ssh -l root <REMOTE HOST> tshark -w - not tcp port 22 | wireshark -k -i -
or using bash :
wireshark -k -i <(ssh -l root <REMOTE HOST> tshark -w - not tcp port 22)
You can use tcpdump instead of tshark if needed :
ssh -l root <REMOTE HOST> tcpdump -U -s0 -w - -i eth0 'port 22' |
wireshark -k -i -
You are connected to a switch which is "switching" traffic. It bases the traffic you see on your mac address. It will NOT send you traffic that is not destined to your mac address. If you want to monitor all the traffic you need to configure your switch to use a "port mirror" and plug your sniffer into that port. There is no software that you can install on your machine that will circumvent the way network switching works.
http://en.wikipedia.org/wiki/Port_mirroring
Im writing a bash scripting to account traffic in my network server:
WAN:eth1 -> GNU/Linux Server:eth0 -> Users
The GNU/Linux server uses squid, bind, QoS, mysql, lighttpd.
After an IP exceed the established quota a new QoS rule is applied for that IP (user) too exist one "flag" to decide when is restored the IP counter to Zero.
Some IPs and subnets work without quotas, other gruop of ips/subnets work with new QoS after quota is exceeded, and now I wanna work with a third group with redirection after quota is exceeded.
When an IP exceed the established quota all http traffic must be redirected to host (lighttpd runing on GNU/Linux ) and DROP all other traffic generated for that IP. In webserver exist a webpage with: "You exceed your daily quote of traffic, please wait "x" hours or call to your provider to purchase an extra navigation package" or something like that.
Is possible using a chain, or how can I do that?.
The most topics that I found in Internet, are related to block all and create a new chain to let out to Internet (not work for me). And other redirect only IP by IP, but how can I create something that a "chain" and attach the IPs to must me redirected to can after restore that IPs easly?
Thanks for help and sorry for my poor English :S.
Are you looking for something like this?
iptables -t nat -A PREROUTING -s 192.168.100.66 -p tcp --dport 80 -j REDIRECT --to-ports 80
iptables -I INPUT 1 -i lo -s 192.168.100.66 -j ACCEPT
iptables -I INPUT 2 -i eth1 -d 192.168.100.66 -j DROP
This will redirect packets from 192.168.100.66 on port 80 to the local webserver on the loopback interface, allow that conversation, then reject all other packets being routed to 192.168.100.66 on the WAN interface.
To restore the connection back to normal you will want to delete those firewall entries:
iptables -t nat -D PREROUTING -s 192.168.100.66 -p tcp --dport 80 -j REDIRECT --to-ports 80
iptables -D INPUT -i lo -s 192.168.100.66 -j ACCEPT
iptables -D INPUT -i eth1 -d 192.168.100.66 -j DROP
Note that iptables itself (well, the xtables-addons extension set providing quota2) can already do the quota matching magic and you can (re)set the values through procfs, combined with REDIRECT as #resmon6 says:
-t nat -s user1addr -m quota2 --name user1 ! --quota 0 -j REDIRECT...
-t nat -s user2addr -m quota2 --name user2 ! --quota 0 -j REDIRECT...
The syntax is a arguably a little odd right now (0 is the initial value only and is independent from the runtime quota test involving the negational !. Noticing this just now, a patch may make it in to unroll this confusing syntax in the future).