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cathy_123's avatar
cathy_123
Icon for Cirrus rankCirrus
Jan 16, 2017

character limit f5 subject alternative name

Guys   I am having issue creating .csr in f5. Do we have limit on character for Subject Alternative names? we have 1111 characters including spaces on Subject alternative name however it has an er...
.csr
BIG-IP
certficate
devops
LTM
san
JG's avatar
JG
Icon for Cumulonimbus rankCumulonimbus
Jan 17, 2017

I have created the following test script and could create some 1000 entries without a problem:

!/bin/sh

cd /tmp
cp /etc/pki/tls/openssl.cnf /tmp/
> /tmp/alt_names

for i in {1..1000}; do echo "DNS.$i=mydomain$i.com" >> /tmp/alt_names; done

echo '[SAN]' >> /tmp/openssl.cnf
echo 'subjectAltName=@alt_names' >> /tmp/openssl.cnf
echo '[alt_names]' >> /tmp/openssl.cnf
cat /tmp/alt_names >> /tmp/openssl.cnf

openssl req -new -sha256 -key domain.key -subj "/C=US/ST=New York/L=New York/O=Example, Inc./CN=example.com/emailAddress=test@example.com" -reqexts SAN -config /tmp/openssl.cnf -out domain.csr
openssl req -text -noout -verify -in domain.csr

There are limits in all systems, but they shouldn't be a problem here.