search for: maxstartup

I have a system where 4 or 5 times now it has locked out new ssh connections. It appears as if MaxStartups is not re-allowing connections when the number of unauthenticated connections drops. Instead, 100% rejection until sshd is restarted. The client (even "ssh localhost") gets one of: kex_exchange_identification: Connection closed by remote host kex_exchange_identification: read: C...

On Thu, 17 Apr 2025, Damien Miller wrote: > I haven't seen this behaviour and can't replicate it manually using > OpenSSH 10.0. I think debugging this will require a log trace with > LogLevel=debug3 if you can manage it. Certainly can. Enabled in sshd_config and now a lot more information in auth.log. These occurances have been quite regular recently, so hopefully won't

https://bugzilla.mindrot.org/show_bug.cgi?id=3832 Bug ID: 3832 Summary: [PATCH] typo: MaxStartups instead of Maxstartups Product: Portable OpenSSH Version: 10.0p2 Hardware: All OS: All Status: NEW Severity: enhancement Priority: P5 Component: sshd Assignee: unassigned-bugs at mindrot.org...

https://bugzilla.mindrot.org/show_bug.cgi?id=3055 Bug ID: 3055 Summary: Need some high-probability logging re MaxStartups Product: Portable OpenSSH Version: 8.0p1 Hardware: Other OS: Linux Status: NEW Severity: normal Priority: P5 Component: sshd Assignee: unassigned-bugs at mindrot.org Reporter: oxwghc at fyv...

I would like some clarification regarding the use of MaxStartups. I have always used the three colon separated value that enables the random drop capabilities, but the documentation for sshd says that MaxStartups can also take a single value which sets a max and leaves random drops off. When I try this, sshd tells me that it got an illegal integer. Looking...

Hello, What is the effect of MaxStartups in the configuration file sshd_config? How this keyword effects the working of sshd? regards Kumaresh -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.mindrot.org/pipermail/openssh-unix-dev/attachments/20020613/8306c832/attachment.html

https://bugzilla.mindrot.org/show_bug.cgi?id=2613 Bug ID: 2613 Summary: Log connections dropped when MaxStartups is reached Product: Portable OpenSSH Version: 7.3p1 Hardware: Sparc OS: Solaris Status: NEW Severity: trivial Priority: P5 Component: sshd Assignee: unassigned-bugs at mindrot.org Reporter:...

...an't replicate it manually using OpenSSH 10.0. I think debugging this will require a log trace with LogLevel=debug3 if you can manage it. On Wed, 16 Apr 2025, Mark Hills wrote: > I have a system where 4 or 5 times now it has locked out new ssh > connections. > > It appears as if MaxStartups is not re-allowing connections when the > number of unauthenticated connections drops. > > Instead, 100% rejection until sshd is restarted.

Hi, We serve a fairly substantial number[1] of ssh connections across our fleet.? We have hit MaxStartups limits in the past and bumped it up a few times (currently at 300), but we have no warning before the limit is reached and connections start being dropped.? What I would love is some sort of instrumentation that could let us see the highest number of concurrent pre-auth connections the current...

The patch below (against openssh 3.2.3p1) adds a CheckMaxStartups option, defaulting to yes, to determine whether sshd calls drop_connection(). The motivation behind this is twofold. In our environment, our timesharing machines get enough incoming connections that will trigger spuriously with the default value (10 forked unauthenticated connections) as well a...

Hi, I am not sure to report this as a bug. so mailing to the list. I have sshd(openssh3.5p1) server running on my router and when i run tcpjunk to that port, sshd gets killed after some time 192.168.71.1 is my sshd server and 192.168.71.4 is my client from where i send my dos attack This is the tcpjunk command i gave to the ssh server #tcpjunk -s 192.168.71.1 -p 22 -c req -i 100 req session

...p://www.openssh.com/portable.html This release fixes several bugs reported since the previous release and extends portability to NeXT and Reliant Unix. As usual, the OpenBSD team has been hard at work further polishing and enhancing OpenSSH. This release brings a new configuration directive "MaxStartups" which mitigates connection flooding attacks, further details are in the sshd man-page. Another noteworthy difference from previous releases is that 'FallBackToRsh' now defaults to 'no'. Users of this feature may need to edit their /etc/ssh_config or ~/.ssh/config files to ac...

...p://www.openssh.com/portable.html This release fixes several bugs reported since the previous release and extends portability to NeXT and Reliant Unix. As usual, the OpenBSD team has been hard at work further polishing and enhancing OpenSSH. This release brings a new configuration directive "MaxStartups" which mitigates connection flooding attacks, further details are in the sshd man-page. Another noteworthy difference from previous releases is that 'FallBackToRsh' now defaults to 'no'. Users of this feature may need to edit their /etc/ssh_config or ~/.ssh/config files to ac...

Other than cranking up logging to debug2, is there a way to better tune logging on a server to see if I am running into max sessions ? On FreeBSD RELENG11 I am periodically seeing connections being refused- 3way handshake not completing or completing and then FINs. Typically, I have a hundred or so connections at one time, but they can bounce up to a few hundred on occasion. Without leaving the

https://bugzilla.mindrot.org/show_bug.cgi?id=3211 Bug ID: 3211 Summary: A Product: Portable OpenSSH Version: 8.3p1 Hardware: Other OS: Linux Status: NEW Severity: security Priority: P5 Component: sshd Assignee: unassigned-bugs at mindrot.org Reporter: kircherlike at

http://bugzilla.mindrot.org/show_bug.cgi?id=93 ------- Additional Comments From jprondak at visualmedia.com 2002-02-02 08:45 ------- Created an attachment (id=16) ssh-add.c patch to search ssh_config for IdentityFile(s) ------- You are receiving this mail because: ------- You are the assignee for the bug, or are watching the assignee.

...bility of the DHEat denial-of-service vulnerability against default OpenSSH settings in cloud environments. I thought those on this list might be interested: https://www.positronsecurity.com/blog/2024-04-23-an-analysis-of-dheat-dos-against-ssh-in-cloud-environments/ A short summary: the default MaxStartup setting is fully ineffective in fixing the problem in low-latency network conditions; it is very easy to force a target to hit 100% CPU utilization in that case. Furthermore, the PerSourceMaxStartups setting is only effective when set to 1, which would only allow one unauthenticated connection at...

Hi, we use OpenSSH_3.8.1p1 and we would like to change the complete printer Spool communication from Unix r-Commands to ssh "OpenSSH". Sometimes, we have problems, because of very high connection set-ups in extremely short time intervals, more than 10 open sessions. The connection set-up is partly declined with the error message: ssh_exchange_identification: Connection closed by remote

...hostsRSAAuthentication no HostbasedAuthentication no RSAAuthentication yes PasswordAuthentication yes PermitEmptyPasswords no UsePAM yes #ChallengeResponseAuthentication no KerberosAuthentication no UseLogin no Banner /usr/local/etc/issue.net Subsystem sftp /usr/libexec/openssh/sftp-server MaxStartups 10:30:60 -- Nick Burrett Network Engineer, Designer Servers Ltd. http://www.dsvr.co.uk

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi folks. Please, someone confirm if i'm right. if i'm wrong, please forgive-me. - -------------------------------------------------------------------------------------------------------------- I've developed a little tool to stress test tcp connections.( Sending syn and answer ack-syn ). that simuates a real tcp connection. (