Article ID: 123551, created on Nov 16, 2014, last review on Oct 6, 2015

  • Applies to:
  • Odin Business Automation Standard 4.5


The value field of a DNS record can not exceed 255 characters. As a result, it is not possible to create a DKIM record with a 2048 bits key cause it requires 411 characters.


As stated if RFC 1035, maximal length of a TXT DNS records is 255 bytes. OBAS handles such kind of records with length not greater than 255 bytes without errors.

However to get around this limitation, per RFC 4408 a TXT or SPF record is allowed to contain multiple strings, which should be concatenated together by the reading application.

3.1.3.  Multiple Strings in a Single DNS record

As defined in [RFC1035] sections 3.3.14 and 3.3, a single text DNS
   record (either TXT or SPF RR types) can be composed of more than one
   string.  If a published record contains multiple strings, then the
   record MUST be treated as if those strings are concatenated together
   without adding spaces.  For example:

   IN TXT "v=spf1 .... first" "second string..."

MUST be treated as equivalent to

   IN TXT "v=spf1 .... firstsecond string..."

SPF or TXT records containing multiple strings are useful in
   constructing records that would exceed the 255-byte maximum length of
   a string within a single TXT or SPF RR record.


The feature request PBAS-29730 has been submitted to implement RFC 4408 specifications in future OBAS versions.

Search Words


unable to add txt record because its too long

DNS record too long

maximal length

txt record 255

400e18f6ede9f8be5575a475d2d6b0a6 caea8340e2d186a540518d08602aa065 624ca542e40215e6f1d39170d8e7ec75 70a5401e8b9354cd1d64d0346f2c4a3e

Email subscription for changes to this article
Save as PDF