warning: hostname does not resolve to IP address

Discussion in 'Server Operation' started by FredZ, Sep 14, 2020.

  1. FredZ

    FredZ Member

    Hello all

    I'm getting these mail warnings in the log.
    Code:
    warning: hostname mail.gw.govt.nz does not resolve to address 192.88.190.2
    nslookup produces this responce.
    Code:
    [email protected]:~# nslookup 192.88.190.2
    2.190.88.192.in-addr.arpa       name = wrcipgw.wrc.govt.nz.
    2.190.88.192.in-addr.arpa       name = mail.gw.govt.nz.
    
    Authoritative answers can be found from:
    190.88.192.in-addr.arpa nameserver = ns.datacom.co.nz.
    190.88.192.in-addr.arpa nameserver = ns1.datacom.co.nz.
    ns.datacom.co.nz        internet address = 202.27.76.100
    ns1.datacom.co.nz       internet address = 202.27.77.100
    However dig produces this responce.
    Code:
    [email protected]:~# dig mail.gw.govt.nz
    
    ; <<>> DiG 9.11.5-P4-5.1+deb10u2-Debian <<>> mail.gw.govt.nz
    ;; global options: +cmd
    ;; Got answer:
    ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 10156
    ;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 3, ADDITIONAL: 5
    
    ;; OPT PSEUDOSECTION:
    ; EDNS: version: 0, flags:; udp: 4096
    ; COOKIE: 7f068b2e8c0537b8dc866d2a5f5eeff78365fc72baf395e8 (good)
    ;; QUESTION SECTION:
    ;mail.gw.govt.nz.               IN      A
    
    ;; ANSWER SECTION:
    mail.gw.govt.nz.        300     IN      CNAME   custom.engage.ubiquity.co.nz.
    custom.engage.ubiquity.co.nz. 84231 IN  A       103.241.84.35
    
    ;; AUTHORITY SECTION:
    ubiquity.co.nz.         84231   IN      NS      ns2.discountdomains.co.nz.
    ubiquity.co.nz.         84231   IN      NS      ns1.discountdomains.co.nz.
    ubiquity.co.nz.         84231   IN      NS      ns3.discountdomains.co.nz.
    
    ;; ADDITIONAL SECTION:
    ns1.discountdomains.co.nz. 84231 IN     A       202.174.116.15
    ns2.discountdomains.co.nz. 84231 IN     A       202.174.114.163
    ns3.discountdomains.co.nz. 84231 IN     A       13.75.179.10
    ns3.discountdomains.co.nz. 84231 IN     AAAA    2603:1010:2::14e
    
    ;; Query time: 35 msec
    ;; SERVER: 192.168.1.20#53(192.168.1.20)
    ;; WHEN: Mon Sep 14 16:22:15 NZST 2020
    ;; MSG SIZE  rcvd: 274
    I'm not sure if this is a configuration issue at my end or at the senders end.

    I am expecting emails from the domain in question, so I'm not surprised to see any messages from the domain in question. But I am surprised I can't recieve those emails.

    Your comments would be most helpfull.

    Regards

    Fred
     
  2. Taleman

    Taleman Well-Known Member HowtoForge Supporter

    Code:
    $ host mail.gw.govt.nz
    mail.gw.govt.nz is an alias for custom.engage.ubiquity.co.nz.
    custom.engage.ubiquity.co.nz has address 103.241.84.35
    custom.engage.ubiquity.co.nz mail is handled by 10 m4.ubiquity.co.nz.
    custom.engage.ubiquity.co.nz mail is handled by 10 m2.ubiquity.co.nz.
    custom.engage.ubiquity.co.nz mail is handled by 10 m3.ubiquity.co.nz.
    custom.engage.ubiquity.co.nz mail is handled by 10 m1.ubiquity.co.nz.
    
    So the warning is correct, mail.gw.govt.nz does not resolve to the used IP address.
    My interpretation is email server at IP address 192.88.190.2 tried to send to your server, and claimed it is mail.gw.govt.nz. Your e-mail server caught this and warned, maybe refused to accept the e-mail.
    Spammers do things like that, claiming to be someone else. Or it is a misconfigured e-mail server, but that must be corrected by admins there, you can not fix that.
     

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