Quote:
Originally Posted by davidfor
"LISTEN" means that an application on the PC is waiting for something to come in on the port. It doesn't mean anything can reach it. "ESTABLISHED" means that something has reached that port.
I'm not sure on the rest. But, some of them work by the local application initiating the connection. They can hold it open or check periodically. They might also negotiate another port to use. The ISP is usually blocking incoming ports, not outgoing, so applications that work like this will be OK.
It's also common for ISPs to block some ports, but not others. Blocking port 25 is common to help prevent spam. My ISP blocks 25 outgoing, 135, 137, 138, 139, 445 both ways and 80, 443, 22, 23, 8080, 3128 incoming. But, I can also turn that off. Another policy I have seen is to block all low numbered ports, but allow high numbers.
Something you can try is to telnet to the ports. Or run a traceroute to the port from outside. Using telnet is handy as is the simplest way of contacting the port. The traceroute can help see where the block is. Unless you know the network well, it will still be a guess, but the domain names of the devices can give a good idea of where the block happens.
And of course, are you sure the where ever you are testing from isn't blocking the port? I have access to several networks at work. They are all restricted, but one of them is almost completely closed to the outside world.
|
Yea, I gotta break down and talk to the ISP and hope they will give me a straight answer.
I am a networking noob, so not sure what you mean by doing a "telnet to the ports"? Do you mean go into terminal mode on the Linux Calibre PC, then go into telnet to look at the ports?
Here is a traceroute to google.com:
traceroute google.com
traceroute to google.com (189.198.236.59), 30 hops max, 60 byte packets
1 unknown (10.0.0.1) 0.260 ms 0.497 ms 0.497 ms (R2 LAN IP)
2 192.168.0.1 (192.168.0.1) 0.719 ms 0.747 ms 0.745 ms (R1 LAN IP)
3 10.46.0.1 (10.46.0.1) 7.814 ms 7.834 ms 7.830 ms
4 10.0.44.62 (10.0.44.62) 8.982 ms 9.154 ms 9.449 ms
5 customer-GYS-static-161-9.megared.net.mx (200.52.161.9) 10.534 ms 11.029 ms 9.776 ms
6 * * *
7 * * *
8 * * *
This continues on for 30 hops with the three ***'s. No clue why this is happening
Here is the traceroute for megacable.com.mx, my ISP:
traceroute megacable.com.mx
traceroute to megacable.com.mx (200.52.196.125), 30 hops max, 60 byte packets
1 unknown (10.0.0.1) 0.231 ms 0.451 ms 0.451 ms
2 192.168.0.1 (192.168.0.1) 0.739 ms 0.769 ms 0.766 ms
3 10.46.0.1 (10.46.0.1) 6.976 ms 7.002 ms 7.674 ms
4 10.0.44.62 (10.0.44.62) 7.850 ms 11.472 ms 11.622 ms
5 customer-GYS-static-161-9.megared.net.mx (200.52.161.9) 13.289 ms 13.221 ms 13.685 ms
6 pe-gys.megared.net.mx (189.199.117.133) 12.257 ms 11.388 ms 7.758 ms
7 10.3.0.25 (10.3.0.25) 45.614 ms * 45.281 ms
8 10.3.0.13 (10.3.0.13) 45.982 ms 44.804 ms 44.738 ms
9 10.3.1.17 (10.3.1.17) 44.797 ms 44.767 ms 44.890 ms
10 10.3.0.97 (10.3.0.97) 48.897 ms 48.062 ms 48.811 ms
11 10.3.1.186 (10.3.1.186) 49.063 ms 76.262 ms 48.799 ms
12 10.3.1.42 (10.3.1.42) 45.735 ms 45.702 ms 45.654 ms
13 10.2.57.1 (10.2.57.1) 48.958 ms 10.2.57.5 (10.2.57.5) 77.822 ms 49.159 ms
14 * * *
15 portalweb.megacable.com.mx (200.52.196.125) 73.375 ms 100.201 ms 73.235 ms
I have attached a screenshot of R1 WAN/LAN setup I forgot to attach for above reply to PeterT.