Mailinabox hosting DNS - TTL

rockman · January 22, 2015, 10:48pm

With Mailinabox configured to host DNS, what is the default TTL for each record?

JoshData · January 22, 2015, 11:04pm

30 minutes. My experience with DNS caching is that these TTLs are kind of a suggestion, though.

mail-in-a-box/mailinabox/blob/master/management/dns_update.py#L371


		ports = []
		t = f.readlines()
		for line in t:
			s = line.split()
			if len(s) == 2 and s[0] == 'Port':
				ports = ports + [s[1]]
	# the keys are the same at each port, so we only need to get
	# them at the first port found (may not be port 22)
	keys = shell("check_output", ["ssh-keyscan", "-t", "rsa,dsa,ecdsa,ed25519", "-p", ports[0], "localhost"])
	for key in sorted(keys.split("\n")):
		if key.strip() == "" or key[0] == "#": continue
		try:
			host, keytype, pubkey = key.split(" ")
			yield "%d %d ( %s )" % (
				algorithm_number[keytype],
				2, # specifies we are using SHA-256 on next line
				hashlib.sha256(base64.b64decode(pubkey)).hexdigest().upper(),
				)
		except:
			# Lots of things can go wrong. Don't let it disturb the DNS
			# zone.

uca · September 14, 2016, 11:07pm

I deleted old cname record and added a new cname records over 6 hours ago and dig is still coming up as my original DNS record.

Locker · March 18, 2018, 4:13pm

I went through dns_update.py and changed 1800 to 3600. What do I need to do to rebuild the zone files so they reflect the new TTL?

If there’s something magic at line 371 for TTL, I’m not seeing it.

benthayer · April 26, 2020, 3:37am

Might be useful for other people:

github.com

mail-in-a-box/mailinabox/blob/f6f75f6fab33f942064194ee28969c5a5a3fca23/management/dns_update.py#L416




	# The SOA contact address for all of the domains on this system is hostmaster
	# @ the PRIMARY_HOSTNAME. Hopefully that's legit.


	# For the refresh through TTL fields, a good reference is:
	# http://www.peerwisdom.org/2013/05/15/dns-understanding-the-soa-record/




	zone = """
$ORIGIN {domain}.
$TTL 1800           ; default time to live


@ IN SOA ns1.{primary_domain}. hostmaster.{primary_domain}. (
           __SERIAL__     ; serial number
           7200     ; Refresh (secondary nameserver update interval)
           1800     ; Retry (when refresh fails, how often to try again)
           1209600  ; Expire (when refresh fails, how long secondary nameserver will keep records around anyway)
           1800     ; Negative TTL (how long negative responses are cached)
           )
"""

You can update the write_nsd_zones function to include whatever TTL you’d like