Terminate established tcp connection using iptables
I have an open socket connection, and I want to close it immediately if packet passing through contains certain string. I have tried the following using iptables:
sudo iptables -A INPUT -p tcp --dport 1342 -m string --algo bm --string ".." -j REJECT
sudo iptables -A INPUT -p tcp --dport 1342 -m string --algo bm --string ".." -j DROP
But none of this works, it just freezes connection permanently. How to "cut" the connection permanently?
Note: as a testing application I have used simple netcat. Firstly, I connected client and listener, then sent the string containing forbidden one. After that, no response was received and no more lines could be sent over this connection, even when REJECT rule was used.
networking scripting iptables
edited Feb 21 at 17:26
Pierre.Vriens
1,00051115
asked Apr 11 '18 at 9:49
nikrom3000nikrom3000
2171211
add a comment |
I have an open socket connection, and I want to close it immediately if packet passing through contains certain string. I have tried the following using iptables:
sudo iptables -A INPUT -p tcp --dport 1342 -m string --algo bm --string ".." -j REJECT
sudo iptables -A INPUT -p tcp --dport 1342 -m string --algo bm --string ".." -j DROP
But none of this works, it just freezes connection permanently. How to "cut" the connection permanently?
Note: as a testing application I have used simple netcat. Firstly, I connected client and listener, then sent the string containing forbidden one. After that, no response was received and no more lines could be sent over this connection, even when REJECT rule was used.
networking scripting iptables
edited Feb 21 at 17:26
Pierre.Vriens
1,00051115
asked Apr 11 '18 at 9:49
nikrom3000nikrom3000
2171211
When you reject a packet a response is sent indicating this. When you drop a packet no response is sent. Most likely the application you are using does not know how to handle the former, and might have a very long timeout (often in the order of minutes) for the latter, to allow for really slow and unreliable network connections. Which application are you trying to control?
– l0b0
Apr 11 '18 at 10:00
@l0b0 as a testing application I have used simple netcat. Firstly, I connected client and listener, then sent the string containing forbidden one. After that, no response was received and no more lines could be sent over this connection, even when REJECT rule was used.
– nikrom3000
Apr 11 '18 at 10:14
add a comment |
I have an open socket connection, and I want to close it immediately if packet passing through contains certain string. I have tried the following using iptables:
sudo iptables -A INPUT -p tcp --dport 1342 -m string --algo bm --string ".." -j REJECT
sudo iptables -A INPUT -p tcp --dport 1342 -m string --algo bm --string ".." -j DROP
But none of this works, it just freezes connection permanently. How to "cut" the connection permanently?
Note: as a testing application I have used simple netcat. Firstly, I connected client and listener, then sent the string containing forbidden one. After that, no response was received and no more lines could be sent over this connection, even when REJECT rule was used.
networking scripting iptables
edited Feb 21 at 17:26
Pierre.Vriens
1,00051115
asked Apr 11 '18 at 9:49
nikrom3000nikrom3000
2171211
I have an open socket connection, and I want to close it immediately if packet passing through contains certain string. I have tried the following using iptables:
sudo iptables -A INPUT -p tcp --dport 1342 -m string --algo bm --string ".." -j REJECT
sudo iptables -A INPUT -p tcp --dport 1342 -m string --algo bm --string ".." -j DROP
But none of this works, it just freezes connection permanently. How to "cut" the connection permanently?
Note: as a testing application I have used simple netcat. Firstly, I connected client and listener, then sent the string containing forbidden one. After that, no response was received and no more lines could be sent over this connection, even when REJECT rule was used.
networking scripting iptables
networking scripting iptables
edited Feb 21 at 17:26
Pierre.Vriens
1,00051115
asked Apr 11 '18 at 9:49
nikrom3000nikrom3000
2171211
edited Feb 21 at 17:26
Pierre.Vriens
1,00051115
asked Apr 11 '18 at 9:49
nikrom3000nikrom3000
2171211
edited Feb 21 at 17:26
Pierre.Vriens
1,00051115
edited Feb 21 at 17:26
Pierre.Vriens
1,00051115
edited Feb 21 at 17:26
Pierre.Vriens
1,00051115
1,00051115
asked Apr 11 '18 at 9:49
nikrom3000nikrom3000
2171211
asked Apr 11 '18 at 9:49
nikrom3000nikrom3000
2171211
asked Apr 11 '18 at 9:49
nikrom3000nikrom3000
2171211
2171211
When you reject a packet a response is sent indicating this. When you drop a packet no response is sent. Most likely the application you are using does not know how to handle the former, and might have a very long timeout (often in the order of minutes) for the latter, to allow for really slow and unreliable network connections. Which application are you trying to control?
– l0b0
Apr 11 '18 at 10:00
@l0b0 as a testing application I have used simple netcat. Firstly, I connected client and listener, then sent the string containing forbidden one. After that, no response was received and no more lines could be sent over this connection, even when REJECT rule was used.
– nikrom3000
Apr 11 '18 at 10:14
add a comment |
When you reject a packet a response is sent indicating this. When you drop a packet no response is sent. Most likely the application you are using does not know how to handle the former, and might have a very long timeout (often in the order of minutes) for the latter, to allow for really slow and unreliable network connections. Which application are you trying to control?
– l0b0
Apr 11 '18 at 10:00
@l0b0 as a testing application I have used simple netcat. Firstly, I connected client and listener, then sent the string containing forbidden one. After that, no response was received and no more lines could be sent over this connection, even when REJECT rule was used.
– nikrom3000
Apr 11 '18 at 10:14
When you reject a packet a response is sent indicating this. When you drop a packet no response is sent. Most likely the application you are using does not know how to handle the former, and might have a very long timeout (often in the order of minutes) for the latter, to allow for really slow and unreliable network connections. Which application are you trying to control?
– l0b0
Apr 11 '18 at 10:00
When you reject a packet a response is sent indicating this. When you drop a packet no response is sent. Most likely the application you are using does not know how to handle the former, and might have a very long timeout (often in the order of minutes) for the latter, to allow for really slow and unreliable network connections. Which application are you trying to control?
– l0b0
Apr 11 '18 at 10:00
@l0b0 as a testing application I have used simple netcat. Firstly, I connected client and listener, then sent the string containing forbidden one. After that, no response was received and no more lines could be sent over this connection, even when REJECT rule was used.
– nikrom3000
Apr 11 '18 at 10:14
@l0b0 as a testing application I have used simple netcat. Firstly, I connected client and listener, then sent the string containing forbidden one. After that, no response was received and no more lines could be sent over this connection, even when REJECT rule was used.
– nikrom3000
Apr 11 '18 at 10:14
add a comment |
1 Answer
1
active
oldest
votes
This I hope does the gig for you. Use REJECT with tcp-reset:
sudo iptables -A INPUT -p tcp --dport 1342 -m string --algo bm --string ".." -j REJECT --reject-with tcp-reset
Try kmp if not worked:
sudo iptables -A INPUT -p tcp --dport 1342 -m string --algo kmp --string ".." -j REJECT --reject-with tcp-reset
answered Apr 11 '18 at 11:28
MTGMTG
112
Actually, it does not terminate Netcat listener
– nikrom3000
Apr 11 '18 at 15:50
Updated my answer. Try kmp as well.
– MTG
Apr 12 '18 at 11:32
it does not work as well. TCP connection does not reset. Tried withNetcatand python'sSimpleHTTPServernow.
– nikrom3000
Apr 13 '18 at 19:22
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
This I hope does the gig for you. Use REJECT with tcp-reset:
sudo iptables -A INPUT -p tcp --dport 1342 -m string --algo bm --string ".." -j REJECT --reject-with tcp-reset
Try kmp if not worked:
sudo iptables -A INPUT -p tcp --dport 1342 -m string --algo kmp --string ".." -j REJECT --reject-with tcp-reset
answered Apr 11 '18 at 11:28
MTGMTG
112
Actually, it does not terminate Netcat listener
– nikrom3000
Apr 11 '18 at 15:50
Updated my answer. Try kmp as well.
– MTG
Apr 12 '18 at 11:32
it does not work as well. TCP connection does not reset. Tried withNetcatand python'sSimpleHTTPServernow.
– nikrom3000
Apr 13 '18 at 19:22
add a comment |
This I hope does the gig for you. Use REJECT with tcp-reset:
sudo iptables -A INPUT -p tcp --dport 1342 -m string --algo bm --string ".." -j REJECT --reject-with tcp-reset
Try kmp if not worked:
sudo iptables -A INPUT -p tcp --dport 1342 -m string --algo kmp --string ".." -j REJECT --reject-with tcp-reset
answered Apr 11 '18 at 11:28
MTGMTG
112
Actually, it does not terminate Netcat listener
– nikrom3000
Apr 11 '18 at 15:50
Updated my answer. Try kmp as well.
– MTG
Apr 12 '18 at 11:32
it does not work as well. TCP connection does not reset. Tried withNetcatand python'sSimpleHTTPServernow.
– nikrom3000
Apr 13 '18 at 19:22
add a comment |
This I hope does the gig for you. Use REJECT with tcp-reset:
sudo iptables -A INPUT -p tcp --dport 1342 -m string --algo bm --string ".." -j REJECT --reject-with tcp-reset
Try kmp if not worked:
sudo iptables -A INPUT -p tcp --dport 1342 -m string --algo kmp --string ".." -j REJECT --reject-with tcp-reset
answered Apr 11 '18 at 11:28
MTGMTG
112
This I hope does the gig for you. Use REJECT with tcp-reset:
sudo iptables -A INPUT -p tcp --dport 1342 -m string --algo bm --string ".." -j REJECT --reject-with tcp-reset
Try kmp if not worked:
sudo iptables -A INPUT -p tcp --dport 1342 -m string --algo kmp --string ".." -j REJECT --reject-with tcp-reset
answered Apr 11 '18 at 11:28
MTGMTG
112
edited Apr 12 '18 at 11:32
answered Apr 11 '18 at 11:28
MTGMTG
112
answered Apr 11 '18 at 11:28
MTGMTG
112
answered Apr 11 '18 at 11:28
MTGMTG
112
112
Actually, it does not terminate Netcat listener
– nikrom3000
Apr 11 '18 at 15:50
Updated my answer. Try kmp as well.
– MTG
Apr 12 '18 at 11:32
it does not work as well. TCP connection does not reset. Tried withNetcatand python'sSimpleHTTPServernow.
– nikrom3000
Apr 13 '18 at 19:22
add a comment |
Actually, it does not terminate Netcat listener
– nikrom3000
Apr 11 '18 at 15:50
Updated my answer. Try kmp as well.
– MTG
Apr 12 '18 at 11:32
it does not work as well. TCP connection does not reset. Tried withNetcatand python'sSimpleHTTPServernow.
– nikrom3000
Apr 13 '18 at 19:22
Actually, it does not terminate Netcat listener
– nikrom3000
Apr 11 '18 at 15:50
Actually, it does not terminate Netcat listener
– nikrom3000
Apr 11 '18 at 15:50
Updated my answer. Try kmp as well.
– MTG
Apr 12 '18 at 11:32
Updated my answer. Try kmp as well.
– MTG
Apr 12 '18 at 11:32
it does not work as well. TCP connection does not reset. Tried with
Netcat and python's SimpleHTTPServer now.– nikrom3000
Apr 13 '18 at 19:22
it does not work as well. TCP connection does not reset. Tried with
Netcat and python's SimpleHTTPServer now.– nikrom3000
Apr 13 '18 at 19:22
add a comment |
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When you reject a packet a response is sent indicating this. When you drop a packet no response is sent. Most likely the application you are using does not know how to handle the former, and might have a very long timeout (often in the order of minutes) for the latter, to allow for really slow and unreliable network connections. Which application are you trying to control?
– l0b0
Apr 11 '18 at 10:00
@l0b0 as a testing application I have used simple netcat. Firstly, I connected client and listener, then sent the string containing forbidden one. After that, no response was received and no more lines could be sent over this connection, even when REJECT rule was used.
– nikrom3000
Apr 11 '18 at 10:14