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What's blocking port 21?
Posted: Thu 20 Nov 2014 7:54 pm
by ironeagleuk
I'm having an infuriating time.
I can't FTP from port 21, something seems to be blocking it upon boot up.
Neither Cumulus & Blue Iris can't upload anything to my website.
The firewall is off, but I had already added Port 21 to that, so it's not that.
It's can't be the router or my ISP as other PC's are able to FTP successfully.
When I first turn on the PC, Cumulus manages to send data, then shortly after, port 21 becomes blocked.
Websites that check for open ports reports that port 21 isn' accessible.
This first started happening Sunday/Monday, then somehow Monday it started working ok.
Last night my puter rebooted itself dues to Windows updates, and today Port 21 is blocked again.
I rolled back using System Restore, but this hasn't helped.
Something somewhere on my PC is blocking port 21, and I can't work out what it could be, does anyone have any clues as to what I can look at?
Re: What's blocking port 21?
Posted: Thu 20 Nov 2014 7:59 pm
by ironeagleuk
Bizarrely whilst posting the above message, it would appear that Cumulus updated my website, but it's back to being blocked again
Re: What's blocking port 21?
Posted: Thu 20 Nov 2014 8:00 pm
by mcrossley
You need ports 20 & 21 open outbound for active FTP, 21 plus a random port above 1023 for passive. The inbound ports are always > 1023.
Re: What's blocking port 21?
Posted: Thu 20 Nov 2014 8:16 pm
by ironeagleuk
I don't think I have ever had port 20 open, and it's been mostly fine for the last 5 years....this is something that has started very recently
Re: What's blocking port 21?
Posted: Thu 20 Nov 2014 10:49 pm
by ironeagleuk
Well this is strange....I stopped my NIC's from being static, and changed both to dynamic, and not had an FTP error in the last 45 minutes
Can anyone explain that?
Re: What's blocking port 21?
Posted: Fri 21 Nov 2014 7:52 am
by ironeagleuk
Ok, so the above doesn't seem to have been the problem....just a coincidence
Overnight my PC installed Windows updates, rebooted itself, and I am having FTP errors again, with dynamic IP addresses
Re: What's blocking port 21?
Posted: Fri 21 Nov 2014 8:26 am
by steve
Are you using active or passive ftp? How do you know that the problem is specifically that something is blocking outbound connections to port 21? What does the Cumulus ftp log show?
Re: What's blocking port 21?
Posted: Fri 21 Nov 2014 7:20 pm
by ironeagleuk
steve wrote:Are you using active or passive ftp? How do you know that the problem is specifically that something is blocking outbound connections to port 21? What does the Cumulus ftp log show?
Hi Steve
I'm using passive I believe.
I can only assume something is, I can't think what else would be wrong. It affects both Blue Iris & Cumulus uploads to my website, but things like realtime.txt seem to work ok...I can't even login using an FTP client, but I can on another PC in my house.
Here's an exrtract of my FTP log
Code: Select all
19:00:02:062 ! HighLevelAsync 0
19:00:02:659 04DC7750 Socket handle created 876
19:00:02:659 TWSocket will connect to 88.208.252.3:21
19:00:23:662 04DC7750 TCustomWSocket.Shutdown 1 876
19:00:23:662 FTPRequestDone ftpConnectAsync Errcode = 10060
19:00:23:662 FTP Connect Error, Error code = 10060
19:00:23:662 ! HighLevelAsync 0
19:00:23:663 04DC7750 Socket handle created 876
19:00:23:663 TWSocket will connect to 88.208.252.3:21
19:00:44:667 04DC7750 TCustomWSocket.Shutdown 1 876
19:00:44:667 FTPRequestDone ftpConnectAsync Errcode = 10060
19:00:44:667 FTP Connect Error, Error code = 10060
19:00:44:667 ! HighLevelAsync 0
19:00:44:668 04DC7750 Socket handle created 876
19:00:44:668 TWSocket will connect to 88.208.252.3:21
19:01:05:672 04DC7750 TCustomWSocket.Shutdown 1 876
19:01:05:672 FTPRequestDone ftpConnectAsync Errcode = 10060
19:01:05:673 FTP Connect Error, Error code = 10060
19:01:05:673 ! HighLevelAsync 0
19:01:05:674 04DC7750 Socket handle created 876
19:01:05:674 TWSocket will connect to 88.208.252.3:21
19:01:26:672 04DC7750 TCustomWSocket.Shutdown 1 876
19:01:26:672 FTPRequestDone ftpConnectAsync Errcode = 10060
19:01:26:672 FTP Connect Timeout
19:05:01:647 ! HighLevelAsync 0
19:05:01:761 04DC7750 Socket handle created 1220
19:05:01:761 TWSocket will connect to 88.208.252.3:21
19:05:22:759 04DC7750 TCustomWSocket.Shutdown 1 1220
19:05:22:759 FTPRequestDone ftpConnectAsync Errcode = 10060
19:05:22:759 FTP Connect Error, Error code = 10060
19:05:22:759 ! HighLevelAsync 0
19:05:22:760 04DC7750 Socket handle created 1220
19:05:22:760 TWSocket will connect to 88.208.252.3:21
19:05:43:756 04DC7750 TCustomWSocket.Shutdown 1 1220
19:05:43:756 FTPRequestDone ftpConnectAsync Errcode = 10060
19:05:43:756 FTP Connect Error, Error code = 10060
19:05:43:756 ! HighLevelAsync 0
19:05:43:757 04DC7750 Socket handle created 1220
19:05:43:757 TWSocket will connect to 88.208.252.3:21
19:06:04:766 04DC7750 TCustomWSocket.Shutdown 1 1220
19:06:04:766 FTPRequestDone ftpConnectAsync Errcode = 10060
19:06:04:767 FTP Connect Error, Error code = 10060
19:06:04:767 ! HighLevelAsync 0
19:06:05:289 04DC7750 Socket handle created 1220
19:06:05:289 TWSocket will connect to 88.208.252.3:21
19:06:21:092 04DC7750 TriggerDataSent 1220
19:06:34:775 ! Aborting
19:06:34:775 FTP Session Closed
19:06:34:775 ! HighLevelAsync 0
19:06:34:775 ! Abort detected
19:06:34:775 ! HighLevelAsync done
19:06:34:776 Connect Timeout
19:06:34:776 FTPRequestDone ftpConnectAsync Errcode = 426
19:06:34:777 FTP Connect Timeout
Re: What's blocking port 21?
Posted: Fri 21 Nov 2014 7:41 pm
by steve
Yes, it's the connect which is timing out, so that does suggest a failure to send anything out to port 21. It's odd that realtime updates are working, as the mechanism is just the same, except that the realtime ftp connection stays connected once established.
Can you connect to any other ftp servers?
Re: What's blocking port 21?
Posted: Fri 21 Nov 2014 9:45 pm
by ironeagleuk
I can only very occasionally login in to another FTP server, but that mostly timeouts too, same as the one for Cumulus.....but my laptop here as been sat FTP'd into my website for the last hour or so without losing the connection
Re: What's blocking port 21?
Posted: Sat 22 Nov 2014 8:23 am
by steve
As an experiment, you could try turning off realtime ftp in Cumulus, then rebooting the PC, to see if that improves the situation at all.
Re: What's blocking port 21?
Posted: Sat 22 Nov 2014 10:30 am
by ironeagleuk
Morning
Thanks for the tip....I left a virus scan running overnight, and it found & removed 5 potential problems....I also unticked the realtime FTP boxes, and rebooted.
Rebooting sped up, and things seem to be uploading now...I have reticked the realtime boxes, and that's working ok too.
I am guessing the threats picked up by the virus scan may have improved things....surprised they have not been picked up previously as I have AVG installed, but this was a scan with Microsoft Security Essentials that found the problems.
Thanks again for your help....will see if things remain stable
Re: What's blocking port 21?
Posted: Sun 30 Nov 2014 2:58 pm
by ironeagleuk
Infuriatingly this is happening again, for no apparent reason...same problem as before, so am doing another virus scan.
It started at about 6:45am, so I don't know what changed at that time to stop port 21 from letting data out.
Everytime I reboot, data gets through briefly, then stops, as though something is loading that is blocking port 21