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Old 07-25-2006, 07:08 AM   #1
LQ Newbie
Registered: Mar 2005
Distribution: Slackware 10
Posts: 14

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telnet works but 'telnet host 25' gives 'no route to host'

Hi guys,
Below is an excerpt of a shell session where I'm trying to see why I can't get at an SMTP server on a particular machine on the 'net. The thing I don't understand is that I get:
- replies from ping to this host,
- a connection refusal for a connect on 23 (fine, it's not running telnet),
- a welcome string for connect on 110 (it's running POP3)
- but for a connect to port 25, I get a 'no route to host'.
Isn't this error an IP error? (But IP routing has been shown to work by TCP tests on the other ports)

I've also included the routing table and a call to ifconfig (eth1 has no cable plugged into it)

linux:~ # telnet foo
Trying foo...
telnet: connect to address Connection refused
linux:~ # telnet foo 110
Trying foo...
Connected to foo.
Escape character is '^]'.
+OK POP3 [foo] v2000.70 server ready
telnet> quit
Connection closed.
linux:~ # telnet foo 25
Trying foo...
telnet: connect to address No route to host


linux:~ # netstat -r
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface * U 0 0 0 eth0
loopback * U 0 0 0 lo
default UG 0 0 0 eth0


linux:~ # ifconfig
eth0 Link encap:Ethernet HWaddr 00:0C:6E:4A:32:AA
inet addr: Bcast: Mask:
inet6 addr: fe80::20c:6eff:fe4a:32aa/64 Scope:Link
RX packets:28564 errors:0 dropped:0 overruns:0 frame:0
TX packets:26507 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:13344471 (12.7 Mb) TX bytes:2387901 (2.2 Mb)
Interrupt:5 Base address:0xa000

eth1 Link encap:Ethernet HWaddr 00:26:54:0E:52:85
inet6 addr: fe80::226:54ff:fe0e:5285/64 Scope:Link
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:4 errors:0 dropped:0 overruns:0 carrier:4
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:828 (828.0 b)
Interrupt:11 Base address:0xb000

lo Link encap:Local Loopback
inet addr: Mask:
inet6 addr: ::1/128 Scope:Host
RX packets:26674 errors:0 dropped:0 overruns:0 frame:0
TX packets:26674 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1619549 (1.5 Mb) TX bytes:1619549 (1.5 Mb)
Old 07-25-2006, 07:27 AM   #2
LQ Newbie
Registered: Mar 2005
Distribution: Slackware 10
Posts: 14

Original Poster
Rep: Reputation: 0
Never mind, thanks for reading...
Thank-you outbound filtering at the ISP
Old 07-25-2006, 07:28 AM   #3
Registered: May 2006
Location: India
Distribution: Redhat
Posts: 49

Rep: Reputation: 15
Do you have firewalls enabled? If yes plz check the entry for smtp(i,e smtp connection is allowed or not)


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