syn match zoneSpecial contained /^[@*.]\s/
syn match zoneTTL contained /\s\@<=\d[0-9WwDdHhMmSs]*\(\s\|$\)\@=/ nextgroup=zoneClass,zoneRRType skipwhite
syn keyword zoneClass contained IN CHAOS CH HS HESIOD nextgroup=zoneRRType,zoneTTL skipwhite
-syn keyword zoneRRType contained A AAAA CAA CERT CNAME DNAME DNSKEY DS HINFO LOC MX NAPTR NS NSEC NSEC3 NSEC3PARAM OPENPGPKEY PTR RP RRSIG SMIMEA SOA SPF SRV SSHFP TLSA TXT nextgroup=zoneRData skipwhite
+syn keyword zoneRRType contained A AAAA APL CAA CERT CNAME DNAME DNSKEY DS HINFO LOC MX NAPTR NS NSEC NSEC3 NSEC3PARAM OPENPGPKEY PTR RP RRSIG SMIMEA SOA SPF SRV SSHFP TLSA TXT nextgroup=zoneRData skipwhite
syn match zoneRData contained /[^;]*/ contains=zoneDomain,zoneIPAddr,zoneIP6Addr,zoneText,zoneNumber,zoneParen,zoneUnknown
syn match zoneIPAddr contained /\<[0-9]\{1,3}\(\.[0-9]\{1,3}\)\{,3}\>/
syn match zoneText contained /"\([^"\\]\|\\.\)*"\(\s\|;\|$\)\@=/
syn match zoneNumber contained /\<[0-9]\+\(\s\|;\|$\)\@=/
-syn match zoneSerial contained /\<[0-9]\{9,10}\(\s\|;\|$\)\@=/
+syn match zoneSerial contained /\<[0-9]\{1,10}\(\s\|;\|$\)\@=/
syn match zoneErrParen /)/
syn region zoneParen contained start="(" end=")" contains=zoneSerial,zoneTTL,zoneNumber,zoneComment