knownports / Ports 0–99 / Port 53

Port53

  • domainDomain Name Server

IANA has registered port 53 to domain on TCP and UDP. Its TLS counterpart, domain-s, is registered on port 853.

  1. 49tacacs
  2. 50re-mail-ck
  3. 1 free
  4. 52xns-time
  5. 53domain
  6. 54xns-ch
  7. 55isi-gl
  8. 56xns-auth
TCP assignedUDP assignedreservedno entryAll 70 assigned numbers in ports 0–99

Registry entries

ServiceProtocolsRegisteredModifiedRFCsOther specs
domainTCPUDP————

Where it sits in the registry

Port 53 is one of 70 numbers with an assignment in ports 0–99 (70.0% of the range). 64 other numbers in the range are assigned on exactly the same transports, TCP and UDP, the usual pattern for older entries. The registry records no registration date for it, as for 69 other numbers in the range; dates were recorded mainly from 2002 on.

Status on each protocol

ProtocolOn port 53Other numbers with the same statusNearest with the same status
TCPassigned to domain5,88752 xns-time
UDPassigned to domain5,50052 xns-time
SCTPno entry5,99952 xns-time
DCCPno entry6,08052 xns-time

5,273 other assigned numbers in the registry have exactly this combination across all four protocols.

The nearest assigned numbers

PortServiceLabelProtocolsRegisteredDistance
49tacacsLogin Host Protocol (TACACS)TCPUDP—4
50re-mail-ckRemote Mail Checking ProtocolTCPUDP—3
52xns-timeXNS Time ProtocolTCPUDP—1
54xns-chXNS ClearinghouseTCPUDP—1
55isi-glISI Graphics LanguageTCPUDP—2
56xns-authXNS AuthenticationTCPUDP—3

Other entries that mention domain

The text domain appears in the name or label of 17 other registry entries. It is a text match, not a statement that the services are related. All 17 in the lookup.

  • 853 domain-s “DNS query-response protocol run over TLS”
  • 1308 odsi “Optical Domain Service Interconnect (ODSI)”
  • 4126 ddrepl “Data Domain Replication Service”
  • 5573 sdmmp “SAS Domain Management Messaging Protocol”
  • 6443 sun-sr-https “Service Registry Default HTTPS Domain”
  • 6480 sun-sr-http “Service Registry Default HTTP Domain”
  • 6484 sun-sr-jms “Service Registry Default JMS Domain”
  • 6485 sun-sr-iiop “Service Registry Default IIOP Domain”
  • 6486 sun-sr-iiops “Service Registry Default IIOPS Domain”
  • 6487 sun-sr-iiop-aut “Service Registry Default IIOPAuth Domain”

Listed in Plain and TLS port pairs