Mails - Host not found (in reply to RCPT TO command)

Discussion in 'Installation/Configuration' started by Jeremy007, Feb 23, 2021.

  1. Jeremy007

    Jeremy007 Member

    Hello HTF Friends,

    Setup : Multi-server
    OS : Ubuntu 16.0.4
    Server type : Nginx
    Databse : mySql
    Services : postfix, dovecot

    I've searching all over and battling with this problem all day and can't seem to figure out what went wrong. Mails stopped working on one of my servers. I get the below posted error every time i try to send a mail from any site hosted on the server.

    Code:
    Feb 23 22:18:59 webserver1 postfix/smtp[16533]: 05DC01F8D8: host mail1.coolwebsite.com[mail1.ServerIP] said: 450 4.7.1 <webserver1.webservice.com>: Helo command rejected: Host not found (in reply to RCPT TO command)
    Feb 23 22:18:59 webserver1 postfix/smtp[16581]: 0A2551F822: host mail1.coolwebsite.com[mail1.ServerIP] said: 450 4.7.1 <webserver1.webservice.com>: Helo command rejected: Host not found (in reply to RCPT TO command)
    
    Code:
    Feb 23 22:01:48 ams1 dovecot: lmtp(15521): Connect from local
    Feb 23 22:01:48 ams1 dovecot: lmtp([email protected]): JK8vBEx7N42ChPPGKJARwfzIP: sieve: msgid=<[email protected]>: stored mail into mailbox 'INBOX'
    Feb 23 22:01:48 ams1 postfix/lmtp[15520]: 0A87094F8G5: to=<in
    Any tips or push in the right direction would be greatly appreciated!

    Regards,
    Jeremy
     
  2. Th0m

    Th0m ISPConfig Developer Staff Member ISPConfig Developer

  3. Jesse Norell

    Jesse Norell ISPConfig Developer Staff Member ISPConfig Developer

    Your server is identifying as webserver1.webservice.com, which apparently isn't resolvable.

    Probably adding to dns would be a quick and easy solution for that, though there are many: you could change it's name, or configure it to identify as a different name, or add that name to dns (or even your server's hosts file might work), or disable unknown hostname rejection.

    If you upgrade to a nightly build (or copy the smtpd_helo_restrictions from it) you even get a few more options: add that server's address to mynetworks, or configure the sites to send with authentication, or configure the webserver hostname in /etc/postfix/helo_access.
     
    Last edited: Feb 24, 2021
  4. Jeremy007

    Jeremy007 Member

    Did but couldn't find anything out of the ordinary. I got the following

    Code:
    ##### SERVER #####
    IP-address (as per hostname): ***.***.***.***
    [WARN] could not determine server's ip address by ifconfig
    [INFO] OS version is Ubuntu 18.04.5 LTS
    
    [INFO] uptime:  17:51:17 up 6 min,  1 user,  load average: 0.58, 0.63, 0.33
    
    [INFO] memory:
                  total        used        free      shared  buff/cache   available
    Mem:           7.8G        3.4G        2.8G        274M        1.4M        3.6G
    Swap:            0B          0B          0B
    
    [INFO] ISPConfig is installed.
    
    ##### ISPCONFIG #####
    ISPConfig version is 3.2.2
    
    
    ##### VERSION CHECK #####
    
    [INFO] php (cli) version is 7.0.33-38+ubuntu16.04.1+deb.sury.org+1
    
    ##### PORT CHECK #####
    
    [WARN] Port 8080 (ISPConfig) seems NOT to be listening
    
    ##### MAIL SERVER CHECK #####
    
    
    ##### RUNNING SERVER PROCESSES #####
    
    [INFO] I found the following web server(s):
            Unknown process (nginx:) (PID 1261)
    [INFO] I found the following mail server(s):
            Postfix (PID 2400)
    [INFO] I found the following pop3 server(s):
            Dovecot (PID 1119)
    [INFO] I found the following imap server(s):
            Dovecot (PID 1119)
    [INFO] I found the following ftp server(s):
            PureFTP (PID 1565)
    ##### LISTENING PORTS #####
    (only           ()
    Local           (Address)
    [localhost]:10023               (1328/postgrey)
    [localhost]:10024               (2478/amavisd-new)
    [localhost]:10025               (2400/master)
    [localhost]:10026               (2478/amavisd-new)
    [localhost]:10027               (2400/master)
    [anywhere]:587          (2400/master)
    [localhost]:6379                (1223/redis-server)
    [localhost]:11211               (1147/memcached)
    [anywhere]:110          (1119/dovecot)
    [anywhere]:143          (1119/dovecot)
    [anywhere]:80           (1261/nginx:)
    [anywhere]:465          (2400/master)
    [anywhere]:8081         (1261/nginx:)
    [anywhere]:21           (1565/pure-ftpd)
    ***.***.***.***:53              (1137/named)
    [localhost]:53          (1137/named)
    ***.***.***.***:53              (848/systemd-resolve)
    [anywhere]:22           (1171/sshd)
    [anywhere]:25           (2400/master)
    [localhost]:953         (1137/named)
    [anywhere]:443          (1261/nginx:)
    [anywhere]:993          (1119/dovecot)
    [anywhere]:995          (1119/dovecot)
    *:*:*:*::*:10024                (2478/amavisd-new)
    *:*:*:*::*:10026                (2478/amavisd-new)
    *:*:*:*::*:3306         (1267/mysqld)
    *:*:*:*::*:587          (2400/master)
    *:*:*:*::*:6379         (1223/redis-server)
    [localhost]10           (1119/dovecot)
    [localhost]43           (1119/dovecot)
    *:*:*:*::*:80           (1261/nginx:)
    *:*:*:*::*:465          (2400/master)
    *:*:*:*::*:8081         (1261/nginx:)
    *:*:*:*::*:21           (1565/pure-ftpd)
    *:*:*:*::*:53           (1137/named)
    *:*:*:*::*:22           (1171/sshd)
    *:*:*:*::*:25           (2400/master)
    *:*:*:*::*:953          (1137/named)
    *:*:*:*::*:443          (1261/nginx:)
    *:*:*:*::*:993          (1119/dovecot)
    *:*:*:*::*:995          (1119/dovecot)
    
    ##### IPTABLES #####
    Chain INPUT (policy ACCEPT)
    target     prot opt source               destination
    f2b-sshd   tcp  --  [anywhere]/0            [anywhere]/0            multiport dports 22
    
    Chain FORWARD (policy ACCEPT)
    target     prot opt source               destination
    
    Chain OUTPUT (policy ACCEPT)
    target     prot opt source               destination
    
    Chain f2b-sshd (1 references)
    target     prot opt source               destination
    REJECT     all  --  ***.***.***.***         [anywhere]/0            reject-with icmp-port-unreachable
    REJECT     all  --  ***.***.***.***        [anywhere]/0            reject-with icmp-port-unreachable
    REJECT     all  --  ***.***.***.***       [anywhere]/0            reject-with icmp-port-unreachable
    REJECT     all  --  ***.***.***.***       [anywhere]/0            reject-with icmp-port-unreachable
    REJECT     all  --  ***.***.***.***         [anywhere]/0            reject-with icmp-port-unreachable
    REJECT     all  --  ***.***.***.***        [anywhere]/0            reject-with icmp-port-unreachable
    REJECT     all  --  ***.***.***.***       [anywhere]/0            reject-with icmp-port-unreachable
    REJECT     all  --  ***.***.***.***         [anywhere]/0            reject-with icmp-port-unreachable
    RETURN     all  --  [anywhere]/0            [anywhere]/0
    
    
     
  5. Jeremy007

    Jeremy007 Member

    Yes, something was fishy about my hostname, manage to solve it but didn't resolve the issue.
     
  6. Jeremy007

    Jeremy007 Member

    Managed to solve it. Found an error in the hostname of my postfix's main.cf file
    Thanks for the help, definitely helped me find the issue.
     
    Last edited: Feb 24, 2021

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