[SOLVED] DNS won't resolve localhost

[ecobrazim]

Hi all,

Here I am again and guess what, I am still stuck with the usual NAT/DNS, although this seems to be purely a DNS problem.

Here is what I get when I try and resolve localhost:

# host localhost
localhost.mydomain.com does not exist (Authoritative answer)

mailq

253A47C3C9     3962 Fri Sep 26 20:19:28  john@mydomain.com
(Host or domain name not found. Name service error for name=localhost type=A: Host not found)
                                         frank@gmail.com

So I thought I'd add a dirty little hack

db.mydomain

localhost   IN A        127.0.0.1

and it looked good

# host localhost
localhost.mydomain.com A       127.0.0.1

until I saw the mailq:

mailq

70D3E7C3CF     4830 Fri Sep 26 20:34:32  john@mydomain.com
                                     (mail for localhost loops back to myself)
                                         frank@gmail.com

Can anyone help me solve this... I am going round in circles.

The DNS is on the zimbra server and the important configs are as follow.

db.local

$TTL    604800
@       IN      SOA     localhost. root.localhost. (
                              3         ; Serial
                         604800         ; Refresh
                          86400         ; Retry
                        2419200         ; Expire
                         604800 )       ; Negative Cache TTL
;
@       IN      NS      localhost.
@       IN      A       127.0.0.1

db.127

$TTL    604800
@       IN      SOA     localhost. root.localhost. (
                              2         ; Serial
                         604800         ; Refresh
                          86400         ; Retry
                        2419200         ; Expire
                         604800 )       ; Negative Cache TTL
;
@                       IN              NS              localhost.
1.0.0   IN      PTR   localhost.

db.mydomain.com

$TTL    604800
@       IN      SOA     mail.mydomain.com. hostmaster.mydomain.com. (
           2008092607           ; Serial
                         604800         ; Refresh
                          86400         ; Retry
                        2419200         ; Expire
                         604800 )       ; Negative Cache TTL
;
                        IN              NS              mail.mydomain.com.
                        IN              MX 10           mail.mydomain.com.
mail                    IN              A                       10.0.0.1

I think this is something obvious but I have been at it for too long.

Any help would be much appreciated.

PS: "order hosts,dns" didin't help.

Thanks
-eco

[grexk]

Did you already check /etc/hosts? It should look like this:

127.0.0.1 localhost
122.0.1.1 computer01.monster.grouop computer01

# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts

[sergioag]

Actually it should be like this:

127.0.0.1 localhost.localdomain localhost
x.x.x.x mail.mydomain.com myhostname

Just replace x.x.x.x with your host's IP address, mail.mydomain.com with the fully-qualified name of your host and myhostname with your box's hostname.

One more thing: the line which has 127.0.0.1 has to stay like that (exactly).

Best regards,

Sergio Aguayo

[ecobrazim]

Hi guys,

Sorry for the late reply but time zones can do that

This is my host file:

/etc/hosts

# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1       localhost.localdomain localhost
10.0.0.1        mail.mydomain.com

It all good right? It's local IP is 10.0.0.1 which is of course NATed.

I put my DNS logs into overdrive but get very little information:

# host localhost
localhost.mydomain.com does not exist (Authoritative answer)

gives me

==> /var/log/named/queries.log <==
27-Sep-2008 05:41:04.542 client 127.0.0.1#32817: query: localhost.mydomain.com IN A +

Any thoughts? I'll soon be uninstalling the whole bind server and reinstalling it bit by bit.

Thanks for your help.
-eco

[sergioag]

Hi

Don't forget to add your hostname after your FQDN. Also, localhost.mydomain.com isn't supposed to be resolved by the DNS server, but by the /etc/hosts file. Maybe adding your hostname as mentioned here could solve the problem.

Best regards,

Sergio Aguayo

[ecobrazim]

sergioag - Thanks for the hint on the hosts file, completely missed the missing host!


OK, so I decided to go back to basics and removed the DNS server from the zimbra server and customed the hosts file as proposed

/etc/hosts

# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1       localhost.localdomain   localhost
127.0.0.1       localhost.mydomain.com localhost
10.0.0.1    mail.mydomain.com          mail

Now, on zimbra, when I run the following I get

# host localhost
localhost.mydomain.com CNAME   mydomain.com
mydomain.com           A       60.25.29.100

so I did a tcpdump from the firewall and sure enough it goes out of it's way to ask someone other than my hosts file

08:38:14.516591 IP 10.0.0.1.32823 > 213.186.33.99.53:  6057+ A? localhost.mydomain.com. (41)
08:38:14.516997 IP 213.186.33.99.53 > 10.0.0.1.32823:  6057 2/5/5 CNAME[|domain]
08:38:14.517181 IP 10.0.0.1.32823 > 213.186.33.99.53:  10089+ A? mydomain.com. (31)
08:38:14.517531 IP 213.186.33.99.53 > 10.0.0.1.32823:  10089 1/5/5 A 60.25.29.100 (229)

A ping does the job.

# ping localhost -c 1
PING localhost.localdomain (127.0.0.1) 56(84) bytes of data.
64 bytes from localhost.localdomain (127.0.0.1): icmp_seq=1 ttl=64 time=0.010 ms

Although host is a DNS command and thus, should probably query only DNSs and not the hosts file, I still think something somewhere in my network configuration is wrong.

How did you (all the people using nated environments with zimbra) have bind/hosts setup?

Thanks
-eco

[ecobrazim]

A little update that seems to confirm a problem with my network settings and my wrong assumption that host only deals with DNS.

# host localhost
localhost has address 127.0.0.1

fw # ps -ef |grep named
bind      2943     1  0 Sep26 ?        00:00:00 /usr/sbin/named -u bind
root      3205  3194  0 08:58 pts/3    00:00:00 grep named

fw # /etc/init.d/bind9 stop
Stopping domain name service...: bind.

fw # host localhost
localhost has address 127.0.0.1

Wish me luck

[ecobrazim]

Hi all,

I ended up solving the problem, but first a bit of fun:

dig gives me:

# dig localhost
; <<>> DiG 9.3.4-P1.1 <<>> localhost
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 48520
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;localhost.                     IN      A

;; ANSWER SECTION:
localhost.              604800  IN      A       127.0.0.1

;; AUTHORITY SECTION:
localhost.              604800  IN      NS      localhost.

;; Query time: 0 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Sat Sep 27 08:51:38 2008
;; MSG SIZE  rcvd: 57

while host gives me:

# host localhost
localhost.mydomain.com does not exist (Authoritative answer)

Any one have a clue why that is. Host was leading me to believe the DNS had a problem while it seems it's host that has one.

I solved my problem by setting the Global and Server MTA settings to localhost.

I had changed these at first whilst in the euphoria of my new mail server thinking I was doing well to put mail.mydomain.com instead of localhost.

Thank you all for your help!
-eco

[Baylink]

Thanks for posting the details of your [SOLUTION]. :-)

[ecobrazim]

Originally Posted by Baylink

Thanks for posting the details of your [SOLUTION]. :-)

It's all about open source and giving back what you can init