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I'm in no way a sysadmin, so bear with me a little.

I have a cloud server running Centos 5. I have Virtualmin/Webmin with a handful of sites running without issue. I also have CSF installed to stop persistent bot attacks.

I can access all my sites HTTP and HTTPS (without SSL) and they work fine.

When I attempt to access my Webmin's web interface

My browser hangs, eventually times out. I can no longer access any of my sites due to CSF adding my IP to the temp disallow list, here's the log entry:

*Port Scan* detected from (GB/United Kingdom/-). 16 hits in the last 187 seconds - *Blocked in csf* for 3600 secs

Once I unblock my IP and add it to the temp allow list, I can access the web UI login page.

Any ideas why the initial request is being disallowed?

share|improve this question
Is port 10000 in your TCP_IN and TCP_OUT settings? – ceejayoz Jan 9 '13 at 17:40
No - I just added them in and it seems to have fixed the issue. Feel free to answer this question and I'll accept it. – Dan J Jan 10 '13 at 12:03
Glad to hear it, will do! – ceejayoz Jan 10 '13 at 16:38
up vote 3 down vote accepted

CSF will consider any hits to ports not whitelisted in csf.cfg's TCP_IN setting to be a port scanning attempt.

Since 10000 is a legitimate port for you, add it to the list in TCP_IN and TCP_OUT and you'll be good to go.

share|improve this answer
If you do this, then anyone can access the Webmin login. We use approved IP addresses and using GLOBAL_DYNDNS in CSF, so we cannot allow port 10000, so in this case for us, this solution is not a solution. Its best to identify the reason for port scanning. We have many port scanning to one server, not our others, very strange. – Laurence Cope Feb 2 '14 at 12:22

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