CNAME and Target
Instructions for working with Adobe Client Care to implement CNAME (Canonical Name) support in Adobe Target. Use CNAME to handle ad blocking issues or ITP-related (Intelligent Tracking Prevention) cookie policies. With CNAME, calls are made to a domain owned by the customer rather than a domain owned by Adobe.
Request CNAME support in Target#
Determine the list of hostnames you need for your SSL certificate (see FAQ below).
For each hostname, create a CNAME record in your DNS pointing to your regular Target hostname
clientcode.tt.omtrdc.net
.For example, if your client code is "cnamecustomer" and your proposed hostname is
target.example.com
, your DNS CNAME record looks similar to:Copied to your clipboardtarget.example.com. IN CNAME cnamecustomer.tt.omtrdc.net.
Fill out this form and include it when you open an Adobe Client Care ticket requesting CNAME support:
- Adobe Target client code:
- SSL certificate hostnames (example:
target.example.com target.example.org
): - SSL certificate purchaser (Adobe is highly recommended, see FAQ): Adobe/customer
- If the customer is purchasing the certificate, also known as "Bring Your Own Certificate" (BYOC), fill out these additional details:
- Certificate organization (example: Example Company Inc):
- Certificate organizational unit (optional, example: Marketing):
- Certificate country (example: US):
- Certificate state/region (example: California):
- Certificate city (example: San Jose):
If Adobe is purchasing the certificate, Adobe works with DigiCert to purchase and deploy your certificate on Adobe's production servers.
If the customer is purchasing the certificate (BYOC), Adobe Client Care sends you the certificate signing request (CSR). Use the CSR when purchasing the certificate through your certificate authority of choice. After the certificate is issued, send a copy of the certificate and any intermediate certificates to Adobe Client Care for deployment.
Adobe Client Care notifies you when your implementation is ready.
Update the
serverDomain
documentation to the new CNAME hostname and setoverrideMboxEdgeServer
tofalse
documentation in your at.js configuration.
Frequently Asked Questions#
The following information answers frequently asked questions about requesting and implementing CNAME support in Target:
Can I provide my own certificate (Bring Your Own Certificate or BYOC)?#
You can provide your own certificate. However, Adobe does not recommend this practice. Management of the SSL certificate lifecycle is easier for both Adobe and you if Adobe purchases and controls the certificate. SSL certificates must be renewed every year. Therefore, Adobe Client Care must contact you every year to obtain a new certificate in a timely manner. Some customers can have difficulty producing a renewed certificate in a timely manner. Your Target implementation is jeopardized when the certificate expires because browsers refuse connections.
If you request a Target bring-your-own-certificate CNAME implementation, you are responsible for providing renewed certificates to Adobe Client Care every year. Allowing your CNAME certificate to expire before Adobe can deploy a renewed certificate results in an outage for your specific Target implementation.
How long until my new SSL certificate expires?#
All Adobe-purchased certificates are valid for one year. See DigiCert's article on 1-year certificates for more information.
What hostnames should I choose? How many hostnames per domain should I choose?#
Target CNAME implementations require only one hostname per domain on the SSL certificate and in the customer's DNS. Adobe recommends one hostname per domain. Some customers require more hostnames per domain for their own purposes (testing in staging, for example), which is supported.
Most customers choose a hostname like target.example.com
. Adobe recommends following this practice, but the choice is ultimately yours. Do not request a hostname of an existing DNS record. Doing so causes a conflict and delays time to resolution of your Target CNAME request.
I already have a CNAME implementation for Adobe Analytics, can I use the same certificate or hostname?#
No, Target requires a separate hostname and certificate.
Is my current implementation of Target impacted by ITP 2.x?#
Apple Intelligent Tracking Prevention (ITP) version 2.3 introduced its CNAME Cloaking Mitigation feature, which is able to detect Adobe Target CNAME implementations and reduces the cookie's expiration to seven days. Currently Target has no workaround for ITP's CNAME Cloaking Mitigation. For more information about ITP, see Apple Intelligent Tracking Prevention (ITP) 2.x.
What kind of service disruptions can I expect when my CNAME implementation is deployed?#
There is no service disruption when the certificate is deployed (including certificate renewals).
However, after you change the hostname in your Target implementation code (serverDomain
in at.js) to the new CNAME hostname (target.example.com
), web browsers treat returning visitors as new visitors. Returning visitors' profile data is lost because the previous cookie is inaccessible under the old hostname (clientcode.tt.omtrdc.net
). The previous cookie is inaccessible due to browser security models. This disruption occurs only on the initial cut-over to the new CNAME. Certificate renewals do not have the same effect because the hostname doesn't change.
What key type and certificate signature algorithm is used for my CNAME implementation?#
All certificates are RSA SHA-256 and keys are RSA 2048-bit, by default. Key sizes larger than 2048-bit are not currently supported.
How can I validate that my CNAME implementation is ready for traffic?#
Use the following set of commands (in the macOS or Linux command-line terminal, using bash and curl >=7.49):
Copy and paste this bash function into your terminal, or paste the function into your bash startup script file (usually
~/.bash_profile
or~/.bashrc
) so the function is available across terminal sessions:Copied to your clipboard1function adobeTargetCnameValidation {2 local hostname="$1"3 if [ -z "$hostname" ]; then4 echo "ERROR: no hostname specified"5 return 16 fi78 local service="Adobe Target CNAME implementation"9 local edges="31 32 34 35 36 37 38"10 local edgeDomain="tt.omtrdc.net"11 local edgeFormat="mboxedge%d%s.$edgeDomain"12 local shardFormat="-alb%02d"13 local shards=514 local shardsFoundCount=015 local shardsFound16 local shardsFoundOutput17 local curlRegex="subject:.*CN=|expire date:|issuer:"18 local curlValidation="SSL certificate verify ok"19 local curlResponseValidation='"OK"'20 local curlEndpoint="/uptime?mboxClient=uptime3"21 local url="https://$hostname$curlEndpoint"22 local sslLabsUrl="https://ssllabs.com/ssltest/analyze.html?hideResults=on&latest&d=$hostname"23 local success="✅"24 local failure="🚫"25 local info="🔎"26 local rule="="27 local horizontalRule="$(seq ${COLUMNS:-30} | xargs printf "$rule%.0s")"28 local miniRule="$(seq 5 | xargs printf "$rule%.0s")"29 local curlVersion="$(curl --version | head -1 | cut -d' ' -f2 )"30 local curlVersionRequired=">=7.49"31 local edgeCount="$(wc -w <<< "$edges" | tr -d ' ')"32 local edge33 local shard34 local currEdgeShard35 local dnsOutput36 local cnameExists37 local endToEndTestSucceeded38 local curlResult3940 for shard in $(seq $shards); do41 if [ "$shardsFoundCount" -eq 0 ]; then42 for edge in $edges; do43 if [ "$shard" -eq 1 ]; then44 currEdgeShard="$(printf "$edgeFormat" "$edge" "")"45 else46 currEdgeShard="$(47 printf "$edgeFormat" "$edge" "$(48 printf -- "$shardFormat" "$shard"49 )"50 )"51 fi52 curlResult="$(curl -vsm20 --connect-to "$hostname:443:$currEdgeShard:443" "$url" 2>&1)"53 if grep -q "$curlValidation" <<< "$curlResult"; then54 shardsFound+=" $currEdgeShard"55 if grep -q "$curlResponseValidation" <<< "$curlResult"; then56 shardsFoundCount=$((shardsFoundCount+1))57 shardsFoundOutput+="\n\n$miniRule $success $hostname [edge shard: $currEdgeShard] $miniRule\n"58 else59 shardsFoundOutput+="\n\n$miniRule $failure $hostname [edge shard: $currEdgeShard] $miniRule\n"60 fi61 shardsFoundOutput+="$(grep -E "$curlRegex" <<< "$curlResult" | sort)"62 if ! grep -q "$curlResponseValidation" <<< "$curlResult"; then63 shardsFoundOutput+="\nERROR: unexpected HTTP response from this shard using $url"64 fi65 fi66 done67 fi68 done6970 echo71 echo "$horizontalRule"72 echo73 echo "$service validation for hostname $hostname:"74 dnsOutput="$(dig -t CNAME +short "$hostname" 2>&1)"75 if grep -qFi ".$edgeDomain" <<< "$dnsOutput"; then76 echo "$success $hostname passes DNS CNAME validation"77 cnameExists=true78 else79 echo -n "$failure $hostname FAILED DNS CNAME validation -- "80 if [ -n "$dnsOutput" ]; then81 echo -e "$dnsOutput is not in the subdomain $edgeDomain"82 else83 echo "required DNS CNAME record pointing to <target-client-code>.$edgeDomain not found"84 fi85 fi8687 curlResult="$(curl -vsm20 "$url" 2>&1)"88 if grep -q "$curlValidation" <<< "$curlResult"; then89 if grep -q "$curlResponseValidation" <<< "$curlResult"; then90 echo -en "$success $hostname passes TLS and HTTP response validation"91 if [ -n "$cnameExists" ]; then92 echo93 else94 echo " -- the DNS CNAME is not pointing to the correct subdomain for ${service}s with Adobe-managed certificates" \95 "(bring-your-own-certificate implementations don't have this requirement), but this test passes as configured"96 fi97 endToEndTestSucceeded=true98 else99 echo -n "$failure $hostname FAILED HTTP response validation --" \100 "unexpected response from $url -- "101 if [ -n "$cnameExists" ]; then102 echo "DNS is NOT pointing to the correct shard, notify Adobe Client Care"103 else104 echo "the required DNS CNAME record is missing, see above"105 fi106 fi107 else108109 echo -n "$failure $hostname FAILED TLS validation -- "110 if [ -n "$cnameExists" ]; then111 echo "DNS is likely NOT pointing to the correct shard or there's a validation issue with the certificate or" \112 "protocols, see curl output below and optionally SSL Labs ($sslLabsUrl):"113 echo ""114 echo "$horizontalRule"115 echo "$curlResult" | sed 's/^/ /g'116 echo "$horizontalRule"117 echo ""118 else119 echo "the required DNS CNAME record is missing, see above"120 fi121 fi122123 if [ "$shardsFoundCount" -ge "$edgeCount" ]; then124 echo -n "$success $hostname passes shard validation for the following $shardsFoundCount edge shards:"125 echo -e "$shardsFoundOutput"126 echo127128 if [ -n "$cnameExists" ] && [ -n "$endToEndTestSucceeded" ]; then129 echo "$horizontalRule"130 echo ""131 echo " For additional TLS/SSL validation, including detailed browser/client support,"132 echo " see SSL Labs (click the first IP address if prompted):"133 echo ""134 echo " $info $sslLabsUrl"135 echo ""136 echo " To check DNS propagation around the world, see whatsmydns.net:"137 echo ""138 echo " $info DNS A records: https://whatsmydns.net/#A/$hostname"139 echo " $info DNS CNAME record: https://whatsmydns.net/#CNAME/$hostname"140 fi141 else142 echo -n "$failure $hostname FAILED shard validation -- shards found: $shardsFoundCount," \143 "expected: $edgeCount"144 if bc -l <<< "$(cut -d. -f1,2 <<< "$curlVersion") $curlVersionRequired" 2>/dev/null | grep -q 0; then145 echo -n " -- insufficient curl version installed: $curlVersion, but this script requires curl version" \146 "$curlVersionRequired because it uses the curl --connect-to flag to bypass DNS and directly test" \147 "each Adobe Target edge shards' SNI confirguation for $hostname"148 fi149 if [ -n "$shardsFoundOutput" ]; then150 echo -e ":\n$shardsFoundOutput"151 fi152 echo153 fi154 echo155 echo "$horizontalRule"156 echo157}158Paste this command (replacing
target.example.com
with your hostname):Copied to your clipboardadobeTargetCnameValidation target.example.comIf the implementation is ready, you see output like below. The important part is that all validation status lines show
✅
rather than🚫
. Each Target edge CNAME shard should showCN=target.example.com
, which matches the primary hostname on the requested certificate (additional SAN hostnames on the certificate aren't printed in this output).Copied to your clipboard1$ adobeTargetCnameValidation target.example.com23==========================================================45Adobe Target CNAME implementation validation for hostname target.example.com:6✅ target.example.com passes DNS CNAME validation7✅ target.example.com passes TLS and HTTP response validation8✅ target.example.com passes shard validation for the following 7 edge shards:910===== ✅ target.example.com [edge shard: mboxedge31-alb02.tt.omtrdc.net] =====11* expire date: Jul 22 23:59:59 2022 GMT12* issuer: C=US; O=DigiCert Inc; CN=DigiCert TLS RSA SHA256 2020 CA113* subject: C=US; ST=California; L=San Jose; O=Adobe Systems Incorporated; CN=target.example.com1415===== ✅ target.example.com [edge shard: mboxedge32-alb02.tt.omtrdc.net] =====16* expire date: Jul 22 23:59:59 2022 GMT17* issuer: C=US; O=DigiCert Inc; CN=DigiCert TLS RSA SHA256 2020 CA118* subject: C=US; ST=California; L=San Jose; O=Adobe Systems Incorporated; CN=target.example.com1920===== ✅ target.example.com [edge shard: mboxedge34-alb02.tt.omtrdc.net] =====21* expire date: Jul 22 23:59:59 2022 GMT22* issuer: C=US; O=DigiCert Inc; CN=DigiCert TLS RSA SHA256 2020 CA123* subject: C=US; ST=California; L=San Jose; O=Adobe Systems Incorporated; CN=target.example.com2425===== ✅ target.example.com [edge shard: mboxedge35-alb02.tt.omtrdc.net] =====26* expire date: Jul 22 23:59:59 2022 GMT27* issuer: C=US; O=DigiCert Inc; CN=DigiCert TLS RSA SHA256 2020 CA128* subject: C=US; ST=California; L=San Jose; O=Adobe Systems Incorporated; CN=target.example.com2930===== ✅ target.example.com [edge shard: mboxedge36-alb02.tt.omtrdc.net] =====31* expire date: Jul 22 23:59:59 2022 GMT32* issuer: C=US; O=DigiCert Inc; CN=DigiCert TLS RSA SHA256 2020 CA133* subject: C=US; ST=California; L=San Jose; O=Adobe Systems Incorporated; CN=target.example.com3435===== ✅ target.example.com [edge shard: mboxedge37-alb02.tt.omtrdc.net] =====36* expire date: Jul 22 23:59:59 2022 GMT37* issuer: C=US; O=DigiCert Inc; CN=DigiCert TLS RSA SHA256 2020 CA138* subject: C=US; ST=California; L=San Jose; O=Adobe Systems Incorporated; CN=target.example.com3940===== ✅ target.example.com [edge shard: mboxedge38-alb02.tt.omtrdc.net] =====41* expire date: Jul 22 23:59:59 2022 GMT42* issuer: C=US; O=DigiCert Inc; CN=DigiCert TLS RSA SHA256 2020 CA143* subject: C=US; ST=California; L=San Jose; O=Adobe Systems Incorporated; CN=target.example.com4445==========================================================4647 For additional TLS/SSL validation, including detailed browser/client support,48 see SSL Labs (click the first IP address if prompted):4950 🔎 https://ssllabs.com/ssltest/analyze.html?hideResults=on&latest&d=target.example.com5152 To check DNS propagation around the world, see whatsmydns.net:5354 🔎 DNS A records: https://whatsmydns.net/#A/target.example.com55 🔎 DNS CNAME record: https://whatsmydns.net/#CNAME/target.example.com5657==========================================================
If this validation command fails on DNS validation but you've already made the necessary DNS changes, you might need to wait for your DNS updates to fully propagate. DNS records have an associated TTL (time-to-live) that dictates cache expiration time for DNS replies of those records. As a result, you might need to wait at least as long as your TTLs. You can use the dig target.example.com
command or the G Suite Toolbox to look up your specific TTLs. To check DNS propagation around the world, see whatsmydns.net.
How do I use an opt-out link with CNAME#
If you are using CNAME, the opt-out link should contain the "client=clientcode
parameter, for example:
https://my.cname.domain/optout?client=clientcode
.
Replace clientcode
with your client code, then add the text or image to be linked to the opt-out URL.
Known limitations#
- QA mode is not sticky when you have CNAME and at.js 1.x because it is based on a third-party cookie. The workaround is to add the preview parameters to each URL you navigate to. QA mode is sticky when you have CNAME and at.js 2.x.
- When using CNAME, it becomes more likely that the size of the cookie header for Target calls increase. Adobe recommends keeping the cookie size under 8 KB.