Running an FTP Server on Eircom Broadband

m_stan

I've been using Eircom broadband for around 18 months now and I'm very happy with it.

I recently downloaded a very useful free dynamic DNS util from www.no-ip.com which is working perfectly, updating my dynamic IP with their DNS server automatically. This allows me to connect to my home pc from work via a DNS name.

I also installed an FTP server at home, but my issue is that so far I have only been able to connect to this server using a connection on either Eircom or NTL. Any attempts to connect to the server on other office connections fail. I have verified that most of these connections do not block any outgoing ports, and my firewall on my server is allowing the incoming connection on several ports I've tried, including 20, 21, 22, 23, 24, 25, 54321, 2020 etc etc

So, my question is, are Eircom somehow only allowing connections from certain ISPs ?

Anyone else out there running an FTP server on Eircom Broadband ? What port are you using ?

Remember - I can connect fine from a friends NTL broadband connection, or on an Eircom ISDN connection, so the issue is not with the server, the incoming ports, or the DNS.

Thanks in advance.

m_stan

fyi - the ISPs that cannot connect to my server include Esat BT, DigiWeb, and MCI. The Esat and MCI connections are leased lines.

These fail, where Eircom and NTL work fine, same settings, same users etc.

Blaster99

I'm running ssh over an Eircom ADSL connection with no-ip etc, works fine. ftpd is pretty insecure so I'm not using that.

Can you ping the firewall from whatever location where FTP isn't working?

It's fairly likely something is up with your office connections. Have you setup proxy settings correctly, if that's required?

Blaster99

I am as I'm writing this connected with ssh to my machine at home over an EsatBT leased line.

m_stan

When I ping the dns name, it times out, yet I can access it on HTTP - I have an eMule Web Interface running on port 12345 which works perfectly. Only FTP that does not work (FileZilla server).

Good to know it works for you though

Blaster99

Routers usually have pings disabled by default. Might be an idea to enable that and make sure pings work everywhere. If ping doesn't work, it's not likely anything else will work.

Blaster99

Actually, forget that. If HTTP works, then you know pings will work.

How about the proxy settings, have you checked them? It's conceivable that you have setup your browser to use a HTTP proxy but not setup FTP to go through the same proxy?

Moriarty

Moved to Nets/Comms.

m_stan

we're not using a proxy on this esat connection (leased line).

I'm totally confused by this one. I might try a different ftp server and setting it up on different ports including the one I know works via http, but somehow I feel this will not resolve anything.

thanks for your advice so far.

ressem

List of checks & Qns

1 What method are you using to confirm that the ftp port is not working?
You tried to connect using both hostname and ip address, using command line telnet?
i.e
telnet ip.add.re.ss 21

2 Your leased lines are presumably connected to a managed Cisco router.
Do these go to a company firewall that might block outgoing ftp connections?
check by
telnet ftp.esat.net 21
and see if you get the welcome.

If you set up the ftp server on port 80 or 8080 (the http ports) I guess everything works?

Possible bottlenecks within your company,
Company FTP Proxy server
Company outgoing Firewall connections blocked

Not a surprise that ICMP is blocked, most home routers will throw it out by default.

Running nmap from the office to your home ip address should tell what ports are detected as open, though will probably set off alarms in the IT room.

Running the shields-up scanner at GRC.com from home should pick up whether your ftp port can be detected by the internet world. I really doubt that Eircom are blocking you.

mneylon

Blocking ICMP is going to lead to breakage, so enable it wherever you can.

Ripwave

blacknight wrote:

Blocking ICMP is going to lead to breakage, so enable it wherever you can.

And don't pay too much attention to Gibsons opinions - his software works, but his editorials are a bit flakey.

m_stan

All great tips and suggestions folks !

Got this working last night. Turns out that a load of conflicting rules I had set on my firewall were causing confusion. I removed all the ones I wasn't using and enabled only the ports I wanted to enable incoming connections one, and hey presto, everything came to life.

Thanks to all who replied - you all helped me figure this out in one way or another, plus I learned some stuff along the way.