Server restarts while scannink its ports
 

Hello.

First of all sorry for my english...

I have a problem with Slacware 10.1 on IBM xSeries 200.
While I am scanning ports from another PC, server restarts, like someone switch his power off, and than on.

There is no about this in logs.
The module for Ethernet is correct.

I have no idea why its happen.

When I installed Win 2000 amd scan ports everything was fine.

Please help me!

Thank You All :)

Any iptables running ? If no maybe enable one rule
to trace the connection like :
Then start your scan, after the reboot there is the packet connection
logged in /var/log/syslog, take a look at that

Ok Thanks, I will try.

I saw the same behaviour some time ago, but this was
a Macintosh machine running OSX 10.2 that did reboot
when I tried to scan its open ports, this happened once
though, so I didn't search deeper

Hello,

Well I did what you write. I have added your roule to the iptables.
When I restarted server and started scanning servers ports from another PC , nothing happens. All is working fine. The server didn't restart.
I have some logs in syslog about network packets.

I have removed this roule from iptables, and restarted server.
Then I scanned ports and server restarts!

Please help me!

Anyway as it is a server, you need some basic firewall config, don't you ?

The rule I posted actually blocks nothing though, it just supposed to log
all incoming packets...

If enabling iptables fixes the problem, go with it, configure some basic
rules, proceed step by step

Ok. You are wright.

I'll try do the same after I build a firewall.
I will let You know if it help.

Thank You very much.

Hello again

I built some easy firewall, in which i deny any connection to my servers ethernet.
Now when i am scanning my servers ports from another PC, i still have this problem. Server restarts automaticly.

I have no idea what to do.

I have even bought new ethernet card, but it didn't help.

Hello Again :)

I have found some information about my server:

1. I have added - *.* /dev/tty12 - to my syslog.conf file - now I can see all logs on my screen.

2. When I scanned my servers ports from another PC about 20 times, each time it restarts whitout any information in syslog. But when I added ad.1 line in syslog.conf and watch the screen of my server, I saw for a very short time some two lines before server restarts.
I don't know why, but this lines in syslog from the screen haven't write in the file in /var/log/messages or /var/log/syslog!

3. I have tried to start scanning ports, and then to stop doing that as fast as possible to write down this lines.
Here they are:

sshd[...]: Did not receive identification string from 192.168.5.11
in.identd[...]: started

This two lines are only on my screen!!!
I cant find them in my /var/log/ files

I have still this problem with scanning my servers ports. Each time I do it, server restarts.

Please help me. I have no idea what to do.

Thanks!

Best grettings

Rafal

well...i hope you solved it by now, but just incase...
i was doing some reading here ...

http://members.cox.net/laitcg/new/intro.html

...and when i read this....

--------------
Slackware 9.x update: With the advent of the hotplug feature in Slackware, spontanious reboots may occur. If this happens to you, try disabling hotplug on startup:
chmod -x /etc/rc.d/rc.hotplug
until you isolate the driver that is causing the problem and put it in /etc/hotplug/blacklist.
---------------

...your Q. came up.

before you switch off hotplug, save the output of " lsmod "
so you know what modules are loaded normally.
afterwards just load the module(s) for your network, and scan the ports to check...

egag

Hi,

I didn't solve my problem yet :(

Still when I'm scanning my servers ports, it restarts automaticly.
I home Your solution will helps.

I tried something with disabling ined program, but it didtn't help.

If it helps, I let you know.

Please tell me how did You find this solution. I have visist this site http://members.cox.net/laitcg/new/intro.html
But cant find any information about my problem.

Thanks a lot.

best regards

Rafal

well...it's not exactly describing your problem there, more a possibility.
as it sais...
-------------
With the advent of the hotplug feature in Slackware, spontanious reboots may occur.
-------------

i would just try it and if no luck there's just one less possibility.
( though i woudn't know many more clues atm.)

egag

Hello

I try to do the hotplug thig with disabiling it, but it didn't help.

The server still restarts when I am scanning its ports.

Do You know maby some compaty which provides some support for Slackware? Maby they can help me?

Thank You anyway!

I was following this thread and I have some info that may be useful.
Awhile ago I had a server that due to a power surge got its power supply damaged, but not enough that it would not boot. However, is I scanned the machine it would reboot just like yours. I put a UPS (to smooth the noise and electrical pics) and ... it worked!!
So I purchased another power supply and that was the end of it.

Hope this helps.

Rick

I first thought that was a hardware problem but it said that it could not
reproduce this behaviour from win 2000 system installed on that
machine, moreover setting an iptable log rule avoided the restart
while scanning the ports...

For me it is a netcard driver problem but I can be wrong (more likely)

rafal_, you said that setting a deny iptable rule does not fix the problem,
could you post this rule ? Also the server has only one netcard interface ?