How to Use dig/nslookup to find SPF, DKIM and DMARC Records for a Domain?

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Updated:April 23, 2021
Document ID:217073

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    Introduction

    This document describes how to use dig/nslookup to find SPF, DKIM, and DMARC records for a domain on Email Security Appliance (ESA) and Cloud Email Security (CES).

    Prerequisites

    Requirements

    Cisco recommends that you have knowledge of these topics:

    • ESA on Async OS 10.0 or later
    • Administrative access to the appliance

    Components Used

    The information in this document is based on all supported ESA hardware models and virtual appliances on Async OS 10.0 or later.

    In order to verify the version information of the appliance from the CLI, enter the version command. In the GUI, navigate to Monitor > System Status.
    Both nslookup and dig commands are supported on current ESA/CES Async OS releases. These commands can be executed through SSH/CLI access to the appliance.

    The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, ensure that you understand the potential impact of any command.

    Sample outputs provided are for domains cisco.com and gmail.com, similar commands can be used for other domains as well.

    SPF

    SPF lookups can be performed with these formats:

    • nslookup  domain txt
    • dig  domain txt

    Note: Substitute the word domain with the appropriate domain you would like to look up.

    For domains with multiple TXT records published, nslookup can fail to list SPF records. In such instances, dig must be used instead.

    This is shown in the example outputs here for cisco.com.

    (Machine lab.esa.com)> nslookup cisco.com txt
TXT="google-site-verification=qPS9ZkoQ-Og1rBrM1_N7z-tNJNy2BVxE8lw6SB2iFdk"
    TTL=21m 8s
    (Machine lab.esa.com)> dig cisco.com txt
;; Warning: Message parser reports malformed message packet.
    ;; Truncated, retrying in TCP mode.
; <<>> DiG 9.11.2 <<>> cisco.com TXT
    ;; global options: +cmd
    ;; Got answer:
    ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 20648
    ;; flags: qr rd ra; QUERY: 1, ANSWER: 25, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
    ;cisco.com. IN TXT
;; ANSWER SECTION:
    cisco.com. 1782 IN TXT "fastly-domain-delegation-w049tcm0w48ds-341317-20210209"
    cisco.com. 1782 IN TXT "v=spf1 redirect=spfa._spf.cisco.com"
    cisco.com. 1782 IN TXT "MS=ms35724259"
    cisco.com. 1782 IN TXT "amazonses:QbUv5pPHGQxRy1vKA0J7Y/biE9oR6MTxOTI1bZIfjsw="
    cisco.com. 1782 IN TXT "fastly-domain-delegation-e9a758d22183504af2d5ab4d9a9853da-20210127"
    cisco.com. 1782 IN TXT "QuoVadis=94d4ae74-ecd5-4a33-975e-a0d7f546c801"
    cisco.com. 1782 IN TXT "atlassian-domain-verification=672RcADvt8BPqsb9gCN2ZC5DoTAhUT8abC1blYKQxi/MHMaGoA/BuvjFMaWRtgd7"
    cisco.com. 1782 IN TXT "google-site-verification=9MlQU9MMQ1jHLMUkONKe6QzZ-ZIGRv0BCD1_rY1Zdmc"
    cisco.com. 1782 IN TXT "SFMC-o7HX74BQ79k7glpt_qjlF2vmZO9DpqLtYxKLwg87"
    cisco.com. 1782 IN TXT "926723159-3188410"
    cisco.com. 1782 IN TXT "docusign=95052c5f-a421-4594-9227-02ad2d86dfbe"
    cisco.com. 1782 IN TXT "amazonses:7LyiKZmpuGja4+KbA4xX3lN69yajYKLkHH4QJcWnuwo="
    cisco.com. 1782 IN TXT "google-site-verification=qPS9ZkoQ-Og1rBrM1_N7z-tNJNy2BVxE8lw6SB2iFdk"
    cisco.com. 1782 IN TXT "zpSH7Ye/seyY61hH8+Rq5Kb+ZJ9hDa+qeFBaD/6sPAAg+2POkGdP0byHb1pFVK9uZgYF2AIosUSZq4MB17oydQ=="
    cisco.com. 1782 IN TXT "duo_sso_verification=AxenLdoqIXzjl2RJzE1BlOfkawDbDFlnbyvjAt8vcjKHBkvYwEMySDRk5QmBd66v"
    cisco.com. 1782 IN TXT "facebook-domain-verification=1zoxo8z7t013gpruxmhc8dkerq47vh"
    cisco.com. 1782 IN TXT "google-site-verification=lW5eqPMJI4VrLc28YW-JBkqA-FDNVnhFCXQVDvFqZTo"
    cisco.com. 1782 IN TXT "facebook-domain-verification=qr2nigspzrpa96j1nd9criovuuwino"
    cisco.com. 1782 IN TXT "apple-domain-verification=qOInipPgso3W8cmK"
    cisco.com. 1782 IN TXT "identrust_validate=JnSSfW+y58dEQju6mVBe8lu1MGFepXI50P27OE1ZZQmL"
    cisco.com. 1782 IN TXT "onetrust-domain-verification=20345dd0c33946f299f14c1498b41f67"
    cisco.com. 1782 IN TXT "mixpanel-domain-verify=2c6cb1aa-a3fb-44b9-ad10-d6b744109963"
    cisco.com. 1782 IN TXT "identrust_validate=Wns4/AOM0Ij2kQCQhzvNbMcoBzxItOa+44O7KF06lIp3"
    cisco.com. 1782 IN TXT "docusign=5e18de8e-36d0-4a8e-8e88-b7803423fa2f"
    cisco.com. 1782 IN TXT "amazonses:mX+ylQj+fJAfh9pr03yIR7YvjKZ1bOo5ABegqM/5pvI="
;; Query time: 0 msec
    ;; SERVER: 127.0.0.1#53(127.0.0.1)
    ;; WHEN: Tue Feb 23 06:03:28 GMT 2021
    ;; MSG SIZE rcvd: 1756

    (Machine lab.esa.com)> nslookup gmail.com txt
TXT="v=spf1 redirect=_spf.google.com"
    TTL=30m
    (Machine lab.esa.com)> dig gmail.com txt

    ; <<>> DiG 9.11.2 <<>> gmail.com TXT
    ;; global options: +cmd
    ;; Got answer:
    ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 14807
    ;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
    ;gmail.com. IN TXT
;; ANSWER SECTION:
    gmail.com. 1800 IN TXT "v=spf1 redirect=_spf.google.com"
    gmail.com. 1800 IN TXT "globalsign-smime-dv=CDYX+XFHUw2wml6/Gb8+59BsH31KzUr6c1l2BPvqKX8="
;; Query time: 85 msec
    ;; SERVER: 127.0.0.1#53(127.0.0.1)
    ;; WHEN: Tue Feb 23 06:05:38 GMT 2021
    ;; MSG SIZE rcvd: 148


    DKIM

    DKIM lookups can be performed with these formats:

    • nslookup selector._domainkey.domain txt
    • dig selector._domainkey.domain txt

    Note: Substitute the words selector and domain with the DKIM selector and domain you would like to look up.

    (Machine lab.esa.com)> nslookup iport._domainkey.cisco.com txt
TXT="v=DKIM1;
    p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCctxGhJnvNpdcQLJM6a/0otvdpzFIJuo73OYFuw6/8bXcf8/p5JG/iME1r9fUlrNZs3kMn9ZdPYvTyRbyZ0UyMrsM3ZN2JAIop3M7sitqHgp8pbORFgQyZxq+L23I2cELq+qw
    tbanjWJzEPpVvrvbuz9QL8CUtS+V5N5ldq8L/lwIDAQAB;"
    TTL=1d
    (Machine lab.esa.com)> dig iport._domainkey.cisco.com txt

    ; <<>> DiG 9.11.2 <<>> iport._domainkey.cisco.com TXT
    ;; global options: +cmd
    ;; Got answer:
    ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 21671
    ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
    ;iport._domainkey.cisco.com. IN TXT
;; ANSWER SECTION:
    iport._domainkey.cisco.com. 86400 IN TXT "v=DKIM1;
    p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCctxGhJnvNpdcQLJM6a/0otvdpzFIJuo73OYFuw6/8bXcf8/p5JG/iME1r9fUlrNZs3kMn9ZdPYvTyRbyZ0UyMrsM3ZN2JAIop3M7sitqHgp8pbORFgQyZxq+L23I2cELq+qw
    tbanjWJzEPpVvrvbuz9QL8CUtS+V5N5ldq8L/lwIDAQAB;"
;; Query time: 2 msec
    ;; SERVER: 127.0.0.1#53(127.0.0.1)
    ;; WHEN: Tue Feb 23 06:41:31 GMT 2021
    ;; MSG SIZE rcvd: 285

    (Machine lab.esa.com)> dig 20161025._domainkey.gmail.com TXT

    ; <<>> DiG 9.11.2 <<>> 20161025._domainkey.gmail.com TXT
    ;; global options: +cmd
    ;; Got answer:
    ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 11798
    ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
    ;20161025._domainkey.gmail.com. IN TXT
;; ANSWER SECTION:
    20161025._domainkey.gmail.com. 1800 IN TXT "k=rsa;
    p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAviPGBk4ZB64UfSqWyAicdR7lodhytae+EYRQVtKDhM+1mXjEqRtP/pDT3sBhazkmA48n2k5NJUyMEoO8nc2r6sUA+/Dom5jRBZp6qDKJOwjJ5R/OpHamlRG+YRJQqR"
    "tqEgSiJWG7h7efGYWmh4URhFM9k9+rmG/CwCgwx7Et+c8OMlngaLl04/bPmfpjdEyLWyNimk761CX6KymzYiRDNz1MOJOJ7OzFaS4PFbVLn0m5mf0HVNtBpPwWuCNvaFVflUYxEyblbB6h/oWOPGbzoSgtRA47SHV53SwZjIsVpb
    q4LxUW9IxAEwYzGcSgZ4n5Q8X8TndowsDUzoccPFGhdwIDAQAB"
;; Query time: 174 msec
    ;; SERVER: 127.0.0.1#53(127.0.0.1)
    ;; WHEN: Tue Feb 23 06:45:01 GMT 2021
    ;; MSG SIZE rcvd: 462
    (Machine lab.esa.com)> nslookup 20161025._domainkey.gmail.com TXT
TXT="k=rsa;
    p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAviPGBk4ZB64UfSqWyAicdR7lodhytae+EYRQVtKDhM+1mXjEqRtP/pDT3sBhazkmA48n2k5NJUyMEoO8nc2r6sUA+/Dom5jRBZp6qDKJOwjJ5R/OpHamlRG+YRJQqR"
    "tqEgSiJWG7h7efGYWmh4URhFM9k9+rmG/CwCgwx7Et+c8OMlngaLl04/bPmfpjdEyLWyNimk761CX6KymzYiRDNz1MOJOJ7OzFaS4PFbVLn0m5mf0HVNtBpPwWuCNvaFVflUYxEyblbB6h/oWOPGbzoSgtRA47SHV53SwZjIsVpb
    q4LxUW9IxAEwYzGcSgZ4n5Q8X8TndowsDUzoccPFGhdwIDAQAB"
    TTL=30m


    DMARC

    DMARC lookups can be performed with these formats:

    • nslookup _dmarc.domain txt
    • dig _dmarc.domain txt

    Note: Substitute the word domain with the domain you would like to look up.

    (Machine lab.esa.com)> nslookup _dmarc.cisco.com txt
TXT="v=DMARC1; p=quarantine; pct=0; fo=1; ri=3600; rua=mailto:cisco@rua.agari.com; ruf=mailto:cisco@ruf.agari.com"
    TTL=30m
    (Machine lab.esa.com)> dig txt _dmarc.cisco.com

    ; <<>> DiG 9.11.2 <<>> _dmarc.cisco.com TXT
    ;; global options: +cmd
    ;; Got answer:
    ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 24522
    ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
    ;_dmarc.cisco.com. IN TXT
;; ANSWER SECTION:
    _dmarc.cisco.com. 1800 IN TXT "v=DMARC1; p=quarantine; pct=0; fo=1; ri=3600; rua=mailto:cisco@rua.agari.com; ruf=mailto:cisco@ruf.agari.com"
;; Query time: 2 msec
    ;; SERVER: 127.0.0.1#53(127.0.0.1)
    ;; WHEN: Tue Feb 23 06:34:15 GMT 2021
    ;; MSG SIZE rcvd: 155

    (Machine lab.esa.com)> nslookup _dmarc.gmail.com txt
TXT="v=DMARC1; p=none; sp=quarantine; rua=mailto:mailauth-reports@google.com"
    TTL=30m
    (Machine lab.esa.com)> dig _dmarc.gmail.com txt

    ; <<>> DiG 9.11.2 <<>> _dmarc.gmail.com TXT
    ;; global options: +cmd
    ;; Got answer:
    ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 28370
    ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
    ;_dmarc.gmail.com. IN TXT
;; ANSWER SECTION:
    _dmarc.gmail.com. 1800 IN TXT "v=DMARC1; p=none; sp=quarantine; rua=mailto:mailauth-reports@google.com"
;; Query time: 85 msec
    ;; SERVER: 127.0.0.1#53(127.0.0.1)
    ;; WHEN: Tue Feb 23 06:35:18 GMT 2021
    ;; MSG SIZE rcvd: 118


    Related Information

    Revision History

    Revision Publish Date Comments
    1.0
    29-Apr-2021
    Initial Release
    TAC Authored

    Contributed by Cisco Engineers

    • Libin Varghese
      Cisco TAC Engineer

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