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.
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 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:function adobeTargetCnameValidation { local hostname="$1" if [ -z "$hostname" ]; then echo "ERROR: no hostname specified" return 1 fi local service="Adobe Target CNAME implementation" local edges="31 32 34 35 36 37 38" local edgeDomain="tt.omtrdc.net" local edgeFormat="mboxedge%d%s.$edgeDomain" local shardFormat="-alb%02d" local shards=5 local shardsFoundCount=0 local shardsFound local shardsFoundOutput local curlRegex="subject:.*CN=|expire date:|issuer:" local curlValidation="SSL certificate verify ok" local curlResponseValidation='"OK"' local curlEndpoint="/uptime?mboxClient=uptime3" local url="https://$hostname$curlEndpoint" local sslLabsUrl="https://ssllabs.com/ssltest/analyze.html?hideResults=on&latest&d=$hostname" local success="✅" local failure="🚫" local info="🔎" local rule="=" local horizontalRule="$(seq ${COLUMNS:-30} | xargs printf "$rule%.0s")" local miniRule="$(seq 5 | xargs printf "$rule%.0s")" local curlVersion="$(curl --version | head -1 | cut -d' ' -f2 )" local curlVersionRequired=">=7.49" local edgeCount="$(wc -w <<< "$edges" | tr -d ' ')" local edge local shard local currEdgeShard local dnsOutput local cnameExists local endToEndTestSucceeded local curlResult for shard in $(seq $shards); do if [ "$shardsFoundCount" -eq 0 ]; then for edge in $edges; do if [ "$shard" -eq 1 ]; then currEdgeShard="$(printf "$edgeFormat" "$edge" "")" else currEdgeShard="$( printf "$edgeFormat" "$edge" "$( printf -- "$shardFormat" "$shard" )" )" fi curlResult="$(curl -vsm20 --connect-to "$hostname:443:$currEdgeShard:443" "$url" 2>&1)" if grep -q "$curlValidation" <<< "$curlResult"; then shardsFound+=" $currEdgeShard" if grep -q "$curlResponseValidation" <<< "$curlResult"; then shardsFoundCount=$((shardsFoundCount+1)) shardsFoundOutput+="\n\n$miniRule $success $hostname [edge shard: $currEdgeShard] $miniRule\n" else shardsFoundOutput+="\n\n$miniRule $failure $hostname [edge shard: $currEdgeShard] $miniRule\n" fi shardsFoundOutput+="$(grep -E "$curlRegex" <<< "$curlResult" | sort)" if ! grep -q "$curlResponseValidation" <<< "$curlResult"; then shardsFoundOutput+="\nERROR: unexpected HTTP response from this shard using $url" fi fi done fi done echo echo "$horizontalRule" echo echo "$service validation for hostname $hostname:" dnsOutput="$(dig -t CNAME +short "$hostname" 2>&1)" if grep -qFi ".$edgeDomain" <<< "$dnsOutput"; then echo "$success $hostname passes DNS CNAME validation" cnameExists=true else echo -n "$failure $hostname FAILED DNS CNAME validation -- " if [ -n "$dnsOutput" ]; then echo -e "$dnsOutput is not in the subdomain $edgeDomain" else echo "required DNS CNAME record pointing to <target-client-code>.$edgeDomain not found" fi fi curlResult="$(curl -vsm20 "$url" 2>&1)" if grep -q "$curlValidation" <<< "$curlResult"; then if grep -q "$curlResponseValidation" <<< "$curlResult"; then echo -en "$success $hostname passes TLS and HTTP response validation" if [ -n "$cnameExists" ]; then echo else echo " -- the DNS CNAME is not pointing to the correct subdomain for ${service}s with Adobe-managed certificates" \ "(bring-your-own-certificate implementations don't have this requirement), but this test passes as configured" fi endToEndTestSucceeded=true else echo -n "$failure $hostname FAILED HTTP response validation --" \ "unexpected response from $url -- " if [ -n "$cnameExists" ]; then echo "DNS is NOT pointing to the correct shard, notify Adobe Client Care" else echo "the required DNS CNAME record is missing, see above" fi fi else echo -n "$failure $hostname FAILED TLS validation -- " if [ -n "$cnameExists" ]; then echo "DNS is likely NOT pointing to the correct shard or there's a validation issue with the certificate or" \ "protocols, see curl output below and optionally SSL Labs ($sslLabsUrl):" echo "" echo "$horizontalRule" echo "$curlResult" | sed 's/^/ /g' echo "$horizontalRule" echo "" else echo "the required DNS CNAME record is missing, see above" fi fi if [ "$shardsFoundCount" -ge "$edgeCount" ]; then echo -n "$success $hostname passes shard validation for the following $shardsFoundCount edge shards:" echo -e "$shardsFoundOutput" echo if [ -n "$cnameExists" ] && [ -n "$endToEndTestSucceeded" ]; then echo "$horizontalRule" echo "" echo " For additional TLS/SSL validation, including detailed browser/client support," echo " see SSL Labs (click the first IP address if prompted):" echo "" echo " $info $sslLabsUrl" echo "" echo " To check DNS propagation around the world, see whatsmydns.net:" echo "" echo " $info DNS A records: https://whatsmydns.net/#A/$hostname" echo " $info DNS CNAME record: https://whatsmydns.net/#CNAME/$hostname" fi else echo -n "$failure $hostname FAILED shard validation -- shards found: $shardsFoundCount," \ "expected: $edgeCount" if bc -l <<< "$(cut -d. -f1,2 <<< "$curlVersion") $curlVersionRequired" 2>/dev/null | grep -q 0; then echo -n " -- insufficient curl version installed: $curlVersion, but this script requires curl version" \ "$curlVersionRequired because it uses the curl --connect-to flag to bypass DNS and directly test" \ "each Adobe Target edge shards' SNI confirguation for $hostname" fi if [ -n "$shardsFoundOutput" ]; then echo -e ":\n$shardsFoundOutput" fi echo fi echo echo "$horizontalRule" echo }
-
Paste this command (replacing
target.example.com
with your hostname):adobeTargetCnameValidation target.example.com
If 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).$ adobeTargetCnameValidation target.example.com ========================================================== Adobe Target CNAME implementation validation for hostname target.example.com: ✅ target.example.com passes DNS CNAME validation ✅ target.example.com passes TLS and HTTP response validation ✅ target.example.com passes shard validation for the following 7 edge shards: ===== ✅ target.example.com [edge shard: mboxedge31-alb02.tt.omtrdc.net] ===== * expire date: Jul 22 23:59:59 2022 GMT * issuer: C=US; O=DigiCert Inc; CN=DigiCert TLS RSA SHA256 2020 CA1 * subject: C=US; ST=California; L=San Jose; O=Adobe Systems Incorporated; CN=target.example.com ===== ✅ target.example.com [edge shard: mboxedge32-alb02.tt.omtrdc.net] ===== * expire date: Jul 22 23:59:59 2022 GMT * issuer: C=US; O=DigiCert Inc; CN=DigiCert TLS RSA SHA256 2020 CA1 * subject: C=US; ST=California; L=San Jose; O=Adobe Systems Incorporated; CN=target.example.com ===== ✅ target.example.com [edge shard: mboxedge34-alb02.tt.omtrdc.net] ===== * expire date: Jul 22 23:59:59 2022 GMT * issuer: C=US; O=DigiCert Inc; CN=DigiCert TLS RSA SHA256 2020 CA1 * subject: C=US; ST=California; L=San Jose; O=Adobe Systems Incorporated; CN=target.example.com ===== ✅ target.example.com [edge shard: mboxedge35-alb02.tt.omtrdc.net] ===== * expire date: Jul 22 23:59:59 2022 GMT * issuer: C=US; O=DigiCert Inc; CN=DigiCert TLS RSA SHA256 2020 CA1 * subject: C=US; ST=California; L=San Jose; O=Adobe Systems Incorporated; CN=target.example.com ===== ✅ target.example.com [edge shard: mboxedge36-alb02.tt.omtrdc.net] ===== * expire date: Jul 22 23:59:59 2022 GMT * issuer: C=US; O=DigiCert Inc; CN=DigiCert TLS RSA SHA256 2020 CA1 * subject: C=US; ST=California; L=San Jose; O=Adobe Systems Incorporated; CN=target.example.com ===== ✅ target.example.com [edge shard: mboxedge37-alb02.tt.omtrdc.net] ===== * expire date: Jul 22 23:59:59 2022 GMT * issuer: C=US; O=DigiCert Inc; CN=DigiCert TLS RSA SHA256 2020 CA1 * subject: C=US; ST=California; L=San Jose; O=Adobe Systems Incorporated; CN=target.example.com ===== ✅ target.example.com [edge shard: mboxedge38-alb02.tt.omtrdc.net] ===== * expire date: Jul 22 23:59:59 2022 GMT * issuer: C=US; O=DigiCert Inc; CN=DigiCert TLS RSA SHA256 2020 CA1 * subject: C=US; ST=California; L=San Jose; O=Adobe Systems Incorporated; CN=target.example.com ========================================================== For additional TLS/SSL validation, including detailed browser/client support, see SSL Labs (click the first IP address if prompted): 🔎 https://ssllabs.com/ssltest/analyze.html?hideResults=on&latest&d=target.example.com To check DNS propagation around the world, see whatsmydns.net: 🔎 DNS A records: https://whatsmydns.net/#A/target.example.com 🔎 DNS CNAME record: https://whatsmydns.net/#CNAME/target.example.com ==========================================================
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.