11-07-2005
Lock active ports
Hello,
How do I lock active TCP ports(eg. during a session)?
The thing Im after is to simulate a broken connection to a specifik port, then bring it back up..
OS solaris 10.
10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
how can I lock my keyboard while I'm away from the computer without using lock command. What other commands gives me the option to lock keyboard device?
thanks (7 Replies)
Discussion started by: dianayun
7 Replies
2. HP-UX
Hi ,
How should i implemet a lock function Hp-ux .
I want to a lock a file through fcntl in Hp-ux .
But is not locking properly .
Thanks
Narendra (7 Replies)
Discussion started by: naren_chella
7 Replies
3. UNIX for Advanced & Expert Users
Hey,
I have few Questions :
1. How to Check/Find who all are the users accessing the server using their id ?
2. How to Check who is the active user or non active user (whose id exists but the access privileges has been removed) ?
I am presently using AIX5.3 as a server.
Please suggest... (3 Replies)
Discussion started by: varungupta
3 Replies
4. AIX
Hi all,
I am new to HACMP. So sorry for the newie question. But I did search the forum and it seems that no one asks this before.
So if a 2-node cluster runs in active-active mode (and the same application), what is the benefit of using HACMP ?
If it runs in active-stanby, it is easy to... (9 Replies)
Discussion started by: qiulang
9 Replies
5. Shell Programming and Scripting
My requirement is
I need to write a program in shell scripting to check 2 TCP unused unique port numbers in SOLARIS and I have to lock the same ports so that it will not be used in any other new process and the same port numbers should be used and locked in the LINUX machine to communicate... (2 Replies)
Discussion started by: sreeramr30
2 Replies
6. UNIX for Advanced & Expert Users
wat is the file name that reveals information that what ports are open in system.. (2 Replies)
Discussion started by: lalit21984
2 Replies
7. Red Hat
Hello all,
If anyone has time, I have a few questions:
How do I do the following in Linux. We are using Red Hat and Oracle Enterprise Linux, which is based on Red Hat too.
1. How to lock the account after a few (like 3) invalid password attempts?
2. How do you lock a screen after 30... (1 Reply)
Discussion started by: nstarz
1 Replies
8. Solaris
Hi,
I need to configure 4 ip address (same subnet and mask) in one ipmp group (two interfaces) in an active active formation (link based). Can some one provide the steps or a tutorial link.
Thanks (2 Replies)
Discussion started by: Mack1982
2 Replies
9. UNIX for Advanced & Expert Users
Hi all,
I have to test some user priviliges. The goal is to be sure that an unauthorized user can't restart some modules (ssh, mysql etc...).
I'm trying to automate it with a shell script but in same cases I got the syslog broadcast message.
Is there any way to simply get a return code... (3 Replies)
Discussion started by: Dedalus
3 Replies
10. Shell Programming and Scripting
#!/bin/bash
for digit in $(seq 1 10)
do
if ping -c1 -w2 192.168.1.$digit &> /dev/null
then
echo "192.168.1.$digit is UP"
else
echo "192.168.1.$digit is DOWN"
fi
done (3 Replies)
Discussion started by: fusetrips
3 Replies
LEARN ABOUT DEBIAN
blackhole
BLACKHOLE(4) BSD Kernel Interfaces Manual BLACKHOLE(4)
NAME
blackhole -- a sysctl(8) MIB for manipulating behaviour in respect of refused TCP or UDP connection attempts
SYNOPSIS
sysctl net.inet.tcp.blackhole[=[0 | 1 | 2]]
sysctl net.inet.udp.blackhole[=[0 | 1]]
DESCRIPTION
The blackhole sysctl(8) MIB is used to control system behaviour when connection requests are received on TCP or UDP ports where there is no
socket listening.
Normal behaviour, when a TCP SYN segment is received on a port where there is no socket accepting connections, is for the system to return a
RST segment, and drop the connection. The connecting system will see this as a ``Connection refused''. By setting the TCP blackhole MIB to
a numeric value of one, the incoming SYN segment is merely dropped, and no RST is sent, making the system appear as a blackhole. By setting
the MIB value to two, any segment arriving on a closed port is dropped without returning a RST. This provides some degree of protection
against stealth port scans.
In the UDP instance, enabling blackhole behaviour turns off the sending of an ICMP port unreachable message in response to a UDP datagram
which arrives on a port where there is no socket listening. It must be noted that this behaviour will prevent remote systems from running
traceroute(8) to a system.
The blackhole behaviour is useful to slow down anyone who is port scanning a system, attempting to detect vulnerable services on a system.
It could potentially also slow down someone who is attempting a denial of service attack.
WARNING
The TCP and UDP blackhole features should not be regarded as a replacement for firewall solutions. Better security would consist of the
blackhole sysctl(8) MIB used in conjuction with one of the available firewall packages.
This mechanism is not a substitute for securing a system. It should be used together with other security mechanisms.
SEE ALSO
ip(4), tcp(4), udp(4), ipf(8), ipfw(8), pfctl(8), sysctl(8)
HISTORY
The TCP and UDP blackhole MIBs first appeared in FreeBSD 4.0.
AUTHORS
Geoffrey M. Rehmet
BSD
January 1, 2007 BSD