Subj : Re: DNS Nodelist available for fsxnet
To   : deon
From : Zip
Date : Sat Nov 11 2023 03:25 pm

Hello Deon!

Thank you for your reply!

On 11 Nov 2023, deon said the following...
 
 de> Although you have mentioned server 83.255.255.1, I actually have an IP
 de> block on 83.255.224.0/24 (perhaps 255.1 uses?). When I enabled the DNS
 de> queries, several servers in this block were hammering clrghouz - 10+
 de> queries a second, and to the same records (so not honouring the TTL).

Yep! That netblock belongs to Tele2, one of the major ISPs here in Sweden (who in recent years acquired a company called ComHem, one of the major players in residential broadband here).

 de> The TTL (negative) cache time might actually be my problem - I may not be
 de> returning the right response for an NXDOMAIN, its something I need to
 de> double check on to be sure (I think I need to included an SOA record in
 de> the authority record of the response), which I'm not doing.

Negative TTLs are a pain, and DNS troubleshooting can be, too! :)

 de> I'll disabled that block for now - let me know if it works for you.

Thanks! It seems that this changed things a little -- querying 83.255.255.1 or 83.255.255.2 multiple times in a row now returns either SERVFAIL or a correct answer in an alternating fashion, e.g.:

bbs@glimmer:~$ host -vvv -t SRV _binkp._tcp.f202.n1.z21.fsxnet.nz 83.255.255.2
Trying "_binkp._tcp.f202.n1.z21.fsxnet.nz"
Using domain server:
Name: 83.255.255.2
Address: 83.255.255.2#53
Aliases:

Host _binkp._tcp.f202.n1.z21.fsxnet.nz not found: 2(SERVFAIL)
Received 51 bytes from 83.255.255.2#53 in 8 ms

bbs@glimmer:~$ host -vvv -t SRV _binkp._tcp.f202.n1.z21.fsxnet.nz 83.255.255.2
Trying "_binkp._tcp.f202.n1.z21.fsxnet.nz"
Using domain server:
Name: 83.255.255.2
Address: 83.255.255.2#53
Aliases:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 44666
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;_binkp._tcp.f202.n1.z21.fsxnet.nz. IN  SRV

;; ANSWER SECTION:
_binkp._tcp.f202.n1.z21.fsxnet.nz. 86238 IN SRV 0 1 24554 scbbs.nsupdate.info.

Received 90 bytes from 83.255.255.2#53 in 4 ms

bbs@glimmer:~$ host -vvv -t SRV _binkp._tcp.f202.n1.z21.fsxnet.nz 83.255.255.2
Trying "_binkp._tcp.f202.n1.z21.fsxnet.nz"
Using domain server:
Name: 83.255.255.2
Address: 83.255.255.2#53
Aliases:

Host _binkp._tcp.f202.n1.z21.fsxnet.nz not found: 2(SERVFAIL)
Received 51 bytes from 83.255.255.2#53 in 8 ms

Judging from the intermittent failures, it appears that some TTL stuff could indeed be affecting things...

Best regards
Zip

--- Mystic BBS v1.12 A49 2023/04/30 (Linux/64)
 * Origin: Star Collision BBS, Uppsala, Sweden (21:1/202)

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