Mail server, binding postfix to an IP address, network unreachable

Question

I configured a DNS service using bind. It works and I created a domain named test.com . The problem is not in how I configured bind, I already have a positive feedback: I tested it using dig, which returns 192.168.13.3 if I ask the IP address of mail.test.com .

I am now trying to assign an IP address to my postfix server, in a way that I can use telnet passing directly mail.test.com as argument and not localhost, this way:

telnet -b mail.test.com 25

But if I try it, it says:

trying 192.168.13.3...
telnet: connect to address 192.168.13.3: No route to host
trying 2000:0:13::3
telnet: connect to address 2000:0:13::1: Network is unreachable

For how setting the postfix IP address I followed this answer: https://serverfault.com/a/489308/168676

And this is how I've set it in the master.cf file (I am only showing the modified part):

smtp      unix  -       -       n       -       -       smtp
    -o smtp_bind_address= 192.168.13.3
relay     unix  -       -       n       -       -       smtp
    -o smtp_bind_address= 192.168.13.3
    -o smtp_fallback_relay=

For editing main.cf I followed a guide

And here I'll show the edited parts:

myhostname = mail.test.com
mydomain = test.com
myorigin = $mydomain
inet_interfaces = all
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
mynetworks_style = host

Of course before trying to connect via telnet to postfix, I've made it start:

sudo /sbin/service postfix start

If I try it with localhost it works and I am able to send mails. So I guess that the problem is in configuring the IP address.

Additional details

ifconfig output:

[root@localhost postfix]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.13.100  netmask 255.255.255.0  broadcast 192.168.13.255
        inet6 fec0::fea9:21c:42ff:fe07:555d  prefixlen 64  scopeid 0x40<site>
        inet6 fe80::21c:42ff:fe07:555d  prefixlen 64  scopeid 0x20<link>
        ether 00:1c:42:07:55:5d  txqueuelen 1000  (Ethernet)
        RX packets 12356  bytes 8090462 (7.7 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 10247  bytes 1423127 (1.3 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 16436
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 0  (Local Loopback)
        RX packets 375  bytes 30453 (29.7 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 375  bytes 30453 (29.7 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

PS: the DNS is reachable at 192.168.13.100, I've manually set it this way:

sudo ifconfig eth0 192.168.13.100 netmask 255.255.255.0 broadcast 192.168.13.255

Feel free to ask more info.

Maybe I'm starting with too obvious, but can you actually `ping mail.test.com`. This definitely is a network issue, not a bind or postfix one. — Lætitia, Apr 09 '13 at 10:57
Run this `sudo ifconfig eth0:0 192.168.13.3 netmask 255.255.255.0 broadcast 192.168.13.255` then restart postfix, and see what happens (with or without the inet_interfaces option set). — NickW, Apr 09 '13 at 11:26
You can't have spaces in the options definition inside `master.cf` (you have one after the equals sign: `smtp_bind_address= 192.168.13.3`) — Marki555, Jun 15 '15 at 05:57
What version of Fedora is this? What firewall configuration are you using? — mattdm, Sep 06 '16 at 21:16

NickW · Answer 1 · 2013-04-09T11:01:21.830

1

You just need to create an interface to bind the 192.168.13.3 address to, you can create a subinterface eth0:0 for example, then bring that up and restart postfix, which will then also bind to the new interface.

edited Apr 09 '13 at 11:01

answered Apr 09 '13 at 10:45

NickW

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Do you mean that I need to do that changing the inet_interfaces value in main.cf? – user168676 Apr 09 '13 at 11:12
By default postfix will bind to all of the local addresses it finds, if you want it to only bind to a certain local address, use this in main.cf `inet_interfaces = 192.168.13.3,127.0.0.1` but first make sure the IP exists on your server! – NickW Apr 09 '13 at 11:18
If I set this value postfix fails to start: it says "Job failed. See system journal and 'systemctl status' for details." . – user168676 Apr 09 '13 at 19:23

Mail server, binding postfix to an IP address, network unreachable

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