I'm unable to run telnet on localhost 25, how do I fix it? [SOLVED]
I am running SuSe 11.1 and am testing out an Exim config, and wanted to confirm everything. I ran "telnet localhost 25" and got "trying 127.0.0.1…." and it just sits there. My local carrier seems to block outbound 25 so i knew testing from home was a waste.
I have already received mail form the system so I know it is working but I am troubled that I cannot telnet locally. I also want to be sure it will accept incoming mail before I move the domain dns over.
I have tried without a firewall installed
I have confirmed exim is set up on 25 and 587 (using daemonsmtpports = 25 : 587) I have been able to telenet in from home on port 587.
Exim hostlist contains 127.0.0.1
Telnet doesn't seem to want to work for anything local!
Anyway if I am missing something please let me know. I have been running SuSE 10x servers for work and at home without any issue so I am a little baffled.
As an aside I did remove the default SuSE firewall and am using Firehol, but as I mentioned above even without a firewall installed localhost telnet doesn't seem to work.
Thanks in advance!
20 Replies
/sbin/ifconfig -a
netstat -anp |grep " LISTEN "
grep "^[^#]" /etc/hosts
server1:~ # /sbin/ifconfig -a
dummy0 Link encap:Ethernet HWaddr 1E:0E:F8:67:6D:A7
BROADCAST NOARP MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
eth0 Link encap:Ethernet HWaddr FE:FD:CF:C0:46:9E
inet addr:XXX.XXX.XXX.XXX Bcast:XXX.XXX.XXX.XXX Mask:255.255.255.0
inet6 addr: fe80::fcfd:cfff:fec0:469e/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:3212 errors:0 dropped:0 overruns:0 frame:0
TX packets:2427 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:825890 (806.5 Kb) TX bytes:2044446 (1.9 Mb)
gre0 Link encap:UNSPEC HWaddr 00-00-00-00-3A-34-36-39-00-00-00-00-00-00-00-00
NOARP MTU:1476 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
ip6tnl0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
NOARP MTU:1460 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
lo Link encap:Local Loopback
LOOPBACK MTU:16436 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
sit0 Link encap:IPv6-in-IPv4
NOARP MTU:1480 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
teql0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
NOARP MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
tunl0 Link encap:IPIP Tunnel HWaddr
NOARP MTU:1480 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
server1:~ # netstat -anp |grep " LISTEN "
tcp 0 0 0.0.0.0:587 0.0.0.0:* LISTEN 3448/exim
tcp 0 0 0.0.0.0:21 0.0.0.0:* LISTEN 3602/vsftpd
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 4574/sshd
tcp 0 0 0.0.0.0:25 0.0.0.0:* LISTEN 3448/exim
tcp 0 0 :::587 :::* LISTEN 3448/exim
tcp 0 0 :::80 :::* LISTEN 3582/httpd2-prefork
tcp 0 0 :::22 :::* LISTEN 4574/sshd
tcp 0 0 :::25 :::* LISTEN 3448/exim
server1:~ # grep "^[^#]" /etc/hosts
127.0.0.1 localhost
::1 localhost ipv6-localhost ipv6-loopback
fe00::0 ipv6-localnet
ff00::0 ipv6-mcastprefix
ff02::1 ipv6-allnodes
ff02::2 ipv6-allrouters
ff02::3 ipv6-allhosts
XXX.XXX.XXX.XXX server1.oi-guild.com server1
ifup lo
then restarting exim, and try telnet again. You're missing a key line, here's part of mine:
alucard@thrawn:~$ /sbin/ifconfig lo
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
[snip]
The name in /etc/hosts shouldn't matter unless you need to use the old server1.oi-guild.com from this Linode.
Also check your /var/log/messages and secure files for hints.
server1:~ # ifup lo
lo
RTNETLINK answers: Invalid argument
Cannot enable interface lo.
interface lo is not up
Guess that explains part of it.
I have been letting Linode manage my IP via dhcp and have not set my address to static, which I guess I should.
/etc/hosts.deny:
http-rman : ALL EXCEPT LOCAL
/etc/hosts.allow is completely remarked out.
/var/log/warn had this:
Dec 27 21:55:37 server1 ifup: Cannot enable interface lo.
Dec 27 21:55:37 server1 ifup-route: interface lo is not up
Dec 27 21:55:51 server1 ifup: Cannot enable interface lo.
Dec 27 21:55:51 server1 ifup-route: interface lo is not up
I think we have a problem….
DEVICE=lo
IPADDR=127.0.0.1
NETMASK=255.0.0.0
NETWORK=127.0.0.0
If you're having problems with gated making 127.0.0.0/8 a martian,
you can change this to something else (255.255.255.255, for example)
BROADCAST=127.255.255.255
ONBOOT=yes
NAME=loopback
On my ubuntu install at home it has a file /etc/network/interfaces and it contains this…
auto lo
iface lo inet loopback
ifcfg-lo:
Loopback (lo) configuration
IPADDR=127.0.0.1
NETMASK=255.0.0.0
NETWORK=127.0.0.0
BROADCAST=127.255.255.255
IPADDR_2=127.0.0.2/8
STARTMODE=onboot
USERCONTROL=no
FIREWALL=no
ifcfg-eth0:
BOOTPROTO='dhcp'
STARTMODE='auto'
NAME=''
BROADCAST=''
ETHTOOLOPTIONS=''
IPADDR=''
MTU=''
NETWORK=''
REMOTEIPADDR=''
USERCONTROL='no'
NETMASK=''
````
I have tried to set my static address to the settings I see in my control panel but I get an error on the netmask onm reboot…then its back to the ajax console…and I need to reset the character set because that screen isn't easy.
I am confised as to why "IPADDR_2=127.0.0.2/8" i in there….
Also should I have a "NAME=loopback" in the ifcfg-lo? I thought Name was an optional field.
Any thoughts on that?
EDIT: Ignore this - I have that already…
To add tot he mystery mySQL is connecting via localhost fine. So it may be purely a telnet issue?
FireHOL: Saving your old firewall to a temporary file: OK
FireHOL: Processing file /etc/firehol/firehol.conf: OK
FireHOL: Activating new firewall (355 rules): OK
Setting up network interfaces:
lo
RTNETLINK answers: Invalid argument
Cannot enable interface lo.
interface lo is not up failed
eth0
RTNETLINK answers: Invalid argument
eth0 (DHCP) . . IP/Netmask: 'xxx.xxx.xxx.xxx' / '255.255.255.0' ('lixx-xxx')
RTNETLINK answers: Invalid argument
Cannot enable interface eth0\. failed
gre0
No configuration found for gre0 unused
ip6tnl0
No configuration found for ip6tnl0 unused
teql0
No configuration found for teql0 unused
tunl0
No configuration found for tunl0 unused
eth0
eth0 DHCP client (dhcpcd) is running
eth0 IP address: XXX.XXX.XXX.XXX/24 done
Setting up service network . . . . . . . . . . . . . . done.
Starting vsftpd done
Starting CRON daemon done
Starting SSH daemon done
Starting service xdm unused
Initializing SMTP port (exim) done
Starting service MySQL done
Starting httpd2 (prefork) done
Master Resource Control: runlevel 5 has been reached
Skipped services in runlevel 5: acpid xdm
Welcome to openSUSE 11.0 (i586) - Kernel 2.6.18.8-linode10 (tty1).
(note: Xs are mine)
Now what seems odd is if eth0 is not up how am I connecting?
ifconfig lo 127.0.0.1 netmask 255.0.0.0
see if its a real problem, or overcomplicated do everything including cleaning the kitchen sink distro networking scripts
If you use "localhost", it will connect via Unix Sockets, rather then via the Loop back adapter, where as if you use 127.0.0.1 it connects via TCP..
@mwalling:
try bringing up lo by hand:
ifconfig lo 127.0.0.1 netmask 255.0.0.0see if its a real problem, or overcomplicated do everything including cleaning the kitchen sink distro networking scripts
This worked!
I was able to telnet localhost after I ran that….so how to fix it?
By setting
# grep DEBUG /etc/sysconfig/network/config
DEBUG="yes"
I was able to get a bit more details out of 'ifup'
# ifup lo -o rc onboot
lo -o rc onboot
lo
lo lo -o rc onboot
unknown option rc ignored
'lo' is not wireless, exiting
RTNETLINK answers: Invalid argument
Cannot enable interface lo.
lo lo -o rc onboot
interface lo is not up
lo lo -o rc onboot
unknown option rc
No services to handle for 'lo lo'
executing additional global start script if-up.d/60-dhcp6c
executing additional global start script if-up.d/SuSEfirewall2
executing additional global start script if-up.d/freeswan
(the parameters on 'ifup' are as it is called in /etc/init.d/network)
Some how it seems to want to go into a section that is trying to set wireless parameters and errors out. I am plugging away trying to trace this down, but my ability to read shell scrips as complex as 'ifup' is a little weak. So the going is rather slow. Anyone with a suggestion on where to look would be welcome.
We might have to take this over to the Novell people. At least I have a support contract with them!
# ip link set up dev lo
RTNETLINK answers: Invalid argument
Have not been able to discover the reason for the failure. This line is suppose to bring up the interface. 'ifconfig $INTERFACE up' will also bring up the interface.
Until I get a real fix for 'ip link set …", I have changed the following starting at line 1033 in /sbin/ifup
#if ! ip link set up dev $INTERFACE \
# ${LLADDR:+address $LLADDR} $LINK_OPTIONS; then
# 'ip link set' is broken using ifconfig SB
if ! ifconfig $INTERFACE up; then
This gets me a lo and starts eth0 at the proper location. (Eth0 was also failing initially, then kick-started in the DHCP section a bit later.)
In setting up eth0 there is one other location that "ip …" will fail. But it is not currently causing me an issue so I will not look into that until later.
I going to be submitting a ticket with Linode to get this looked at, I believe it is a problem specific to the linode build as I do not see the issue on other systems that I have with SUSE 11.0 on them.
Mike from Linode support suggested that I try rebooting with '2.6.27.4-linode14' as the kernel selected. With this kernel, startup scripts look to be working as expected.
@seanmb:
This seems to be an issue with the 'Latest 2.6 Series (2.6.18.8-linode10)' kernel.
Mike from Linode support suggested that I try rebooting with '2.6.27.4-linode14' as the kernel selected. With this kernel, startup scripts look to be working as expected.
No other issues around the different kernel?
BTW good find there.
BTW: I like how if you launch the ajax console before booting you can watch the boot process.
@Bedevere:
BTW: I like how if you launch the ajax console before booting you can watch the boot process.
You should be able to do that as well if you ssh to your