telnet can't figure out route to host, but only on certain ports?

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telnet can't figure out route to host, but only on certain ports?

This only occurs under 10.5. In 10.4.11, I can hit the server on both ports through telnet.

telnet <server> 510

Trying <server>...
telnet: connect to address <server>: Connection refused
telnet: Unable to connect to remote host

telnet <server> 80

Trying <server>...
Connected to <server>.
Escape character is '^]'.
fetch
HTTP/1.1 400
Date: Sun, 06 Jul 2008 03:06:15 GMT
Content-Type: text/html

<html><head><title></title></head>
<body>

fetch: 0
</body></html>
Connection closed by foreign host.

Here's the strangest part:

ping <server>
PING <server> (ip): 56 data bytes
ping: sendto: No route to host
^C
--- <server> ping statistics ---
1 packets transmitted, 0 packets received, 100% packet loss

How come it can figure out the route when using port 80, but not when using port 510? And is the inability to figure out the route the reason why Wireshark shows ZERO outgoing packets on port 510 when it fails to connect?

And why only on certain IPs? If I use "edu.yorku.ca", I can connect via telnet on both 80 and 510.

1.83 GHz Intel Core Duo Mini, Mac OS X (10.5.4), 2GB RAM

Posted on Jul 5, 2008 8:13 PM

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Answer 1

orangekay

Level 5

4,085 points

Jul 5, 2008 8:38 PM in response to Jabrwock182

Are you the administrator of the network you're using?

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Answer 2

jabrwock

Level 1

4 points

Jul 9, 2008 12:25 PM in response to orangekay

I'm on a 2Wire router/modem, which is hooked into my local telco via DSL.

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Answer 3

orangekay

Level 5

4,085 points

Jul 9, 2008 12:40 PM in response to Jabrwock182

So it works if you supply a FQDN but not an IP? Are you certain that the IP you're using is valid? There may be some DNS trickery going on behind the scenes.

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Answer 4

Jabrwock182 Author

Level 1

0 points

Aug 1, 2008 7:34 PM in response to orangekay

orangekay wrote:
So it works if you supply a FQDN but not an IP? Are you certain that the IP you're using is valid? There may be some DNS trickery going on behind the scenes.

No, it only connects when I hit the server on port 80. Using IP or FQDN doesn't seem to make a difference.

If I try to use Network Utils to do a trace route, it too says no route to host.

I've got a G4/ppc running 10.4.11 attached to the same router, and it has no issue hitting the server on any port, and can do a trace route as well.

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