Problems with FTP and ping timesout

[Ekliptic]

Hi All,

Wondering if you could help me with a problem. I have multiple friends who have an ftp that everyone else can connect to but I can't. When I try to connect with my ftp client connection failed(connection lost). When I try to ping their ip it times out. What's really odd is that I can connect to other ftp's no problem. Their ftp server is active as I've been able to connect from other computers (not on my network). There are no firewalls involved at either end as well.

Any help on this would be much appreciated.

 

[pansophic]

I'd start with tracert and find out if packets are being dropped somewhere between the two of you. The fact that it only occurs from your computer indicates that your ISP may be filtering certain activities, or there is a firewall involved that you don't know about.

You may also want to try command line ftp and IE and/or Netscape to do the FTP. Command line ftp uses ports 20 and 21 to data transfer and login, while a web browser uses PASV mode, where everything occurs over port 21.

If you are Linux literate at all, there are some better route tracing utilities that will allow you to run a TCP traceroute with specified source and destination ports. They are very effective for trouble shooting this type of problem. Take a look at HPING if you want to know more.
pansophic

 

[Ekliptic]

Hey Pansophic,

Thanks for replying. I tried a tracert and it times out as well. I even used visual route and it said no nodes are responding. This is odd as I can surf the net but not ping this guys ip. I tried ftp through IE as well and it can't connect.... same problem. I'm wondering if I have something on my box that doesn't let me connect/ping his machine.... is there an ip configuration that would prevent me from seeing his machine? Sorry, I'm a noob with all this TCP/IP stuff.

I'm not a Linux user but I picked up Visual Route and it seemed to explain things in plain english.

Any other ideas?

 

[pansophic]

You say that tracert timed out? At what point, the first hop, or somewhere else along the way? Can you tracert to

http://www.yahoo.com?

It is not odd necessarily that you can't ping. Lots of organizations block ICMP because more bad things can happen than good. Tracert uses ICMP as well, so if you can't do either, then it is likely that there is some filtering occurring.

Surfing uses TCP and it uses common (well known) ports, so even when people are filtering, it is likely that they won't filter port 80 (web) or ports 25, 110, 143 (mail).

How do you interface the Internet? Are you using XP? Do you have a cable modem? DSL? Each of these have the ability to filter packets, so the next step is to figure out where it is happening. The fact that tracert doesn't show you anything indicates that the filtering is occurring extremely close to you. Probably on your own machine.
pansophic

 

[Ekliptic]

That's what I had figured as well. The tracert would fail even before the first hop which made me think that it was my machine but no matter what I did I couldn't get it to hop out of my machine to the next node. I was however able to get this fixed. What I did is phoned my isp's upstream provider and worked with them on it. They phoned my isp in a 3 way call and we found that my isp was phasing out a set of ip's on a redirected subnet. This resulted in that I could get to some addresses but none that were in the same subnet as I was hence I couldn't get to my friend's machine. Basically it all came down to the fact that my isp didn't know what they were doing. Apparently I wasn't the only one having problems so they brought in an internet consultant to fix the problems and advise them on additional changes. Anyway, thanks for your help panasophic... I really appreciated it.