Updating DNS entry with mismatched TTL fails

[mmakaay]

Update: the original title of the issue reported issues with updating the @ entery in DNS, but I changed it after finding out the actual issue at hand. See this message for the TL;DR

I have setup transip-dyndns (latest version) and a configuration file with these records to update:

[[record]]
hostname = "makaay.nl"
entry = "here-is"
ttl = 60
type = "A"

[[record]]
hostname = "makaay.nl"
entry = "@"
ttl = 60
type = "A"

When the target records already contain the correct IP addresses as content, things are peachy:

DEBUG - Log level set to debug...
DEBUG - Found IP address. (145.144.245.6)
DEBUG - DNS [A] record has not been changed.
2024-02-22 15:01:08 - 👍  Record still up to date: here-is.makaay.nl [A]
2024-02-22 15:01:08 - 👍  Record still up to date: @.makaay.nl [A]

However, when my IP address changes, updating the @ entry fails. Here is what happens if I update the @ record and then run the program (last line with added line break for readability):

DEBUG - Log level set to debug...
DEBUG - Found IP address. (145.144.245.6)
DEBUG - DNS [A] record has not been changed.
2024-02-22 15:06:13 - 👍  Record still up to date: here-is.makaay.nl [A]
2024-02-22 15:06:13 - ❗  Could not update the record to update @.makaay.nl [A] -
                          Could not find match for DNS entry '@ 60 A'

[mmakaay]

Trying curl against the TransIP API shows me that I have the following record:

{"name":"@","expire":300,"type":"A","content":"192.87.156.100"}

Performing this query:

curl -X PATCH \
    -H "Content-Type: application/json" \
    -H "Authorization: Bearer ****" \    -d '
    {
      "dnsEntry": {
        "name": "@",
        "expire": 60,
        "type": "A",
        "content": "77.174.229.213"
      }
    }
    ' \
    "https://api.transip.nl/v6/domains/makaay.nl/dns"

Does result in the error that I see in the logs:

{"error":"Could not find match for DNS entry '@ 60 A'"}

I think this means that the issue is to be found at the TransIP API side of things here, and not directly in go-transip-dyndns.

[mmakaay]

Hmmm, interestingly enough, my curl-based patch request does work when the expire time matches the current expire time as defined in the TransIP DNS! I was able to update the DNS entry using the structure:

    {
      "dnsEntry": {
        "name": "@",
        "expire": 300,
        "type": "A",
        "content": "77.174.229.213"
      }
    }

Apparently, the expire time is included by the TransIP API in finding the record to update, which is a bit weird IYAM. By playing with the expiry time in the records that I defined, I am able to change the output of transip-dyndns:

DEBUG - Log level set to debug...
DEBUG - Found IP address. (145.144.245.6)
2024-02-22 15:27:34 - ❗  Could not update the record to update here-is.makaay.nl [A] - Could not find match for DNS entry 'here-is 300 A'
2024-02-22 15:27:34 - 👍  Record updated @.makaay.nl [A] to 145.144.245.6

In this case, the @ record has a TTL that matches the active TTL and here-is.makaay.nl has a mismatching TTL. And when I make sure tat the TTL matches for both the records, then both get updated correctly.

[mmakaay]

TL;DR: when the active TTL from the TransIP DNS server differs from the ttl: field as defined in the TOML config, then updating the content for a DNS record through the TransIP API results in an error: "Could not find match for DNS entry '@ A" . When making sure the TTL matches the active one, updates do work correctly.

I think a good solution would be to:

• clarify in the documentation that [[record]] ttl is only used when creating a new DNS record
• let the PATCH request use the TTL as retrieved earlier via the API, instead of the TTL from the TOML config

And thanks for this project! Except for the little speed bump from above, it made it really simple to setup my own dyndns based on my TransIP domains 👍