it's a complex subject, both the software, and the topic, spam.
there are many ways to solve a problem:
DIY php (or pay), turn key plugins, or mix of all the above. only you know what is best for you. (and what is built in) see configuration + settings + general.... page in your ACP.
so you are really asking, 2 topics , registered users and guests.
this current topic covers registered users controls to the nth degree. lots of controls (and very good, ive gone 3 days now and zero spam , a blessing)
but pure guests, that is near impossible to control. (like CB radio , remember that? , wide open noise)
Apples and oranges (guests over reg users, really , add tons if requirements to guests and bingo, it's not really a guest, is it?)
the captcha is off by default (IIRC) so , is not an issue with you.
the main config page shows 3 options, on, off , recaptcha. for Captcha.
for register'd users, you have vast choices, even long user names and PW. mixed case or system create to for you and sends it to the user, or admin activates each user 1 by 1, all this and more and is built in.
The reg user features are ROBUST.
read the manual. it's all there, but controlling spam is a larger topic. and is complex and if you have guests, near impossible to control.
unless you want to Captcha , at each post and add other pop ups asking other questions during all posts. My guess, is you wont like that.?
human interface, you can make it any why you want.
there are no limits. (you are the architect here. )
FYI:
google mybb plugin's see all those choices, ? and providers, !
google how to control spam, on forums. there are millions of pages on topic. y2000 to now. ( pure torture to read)\
all of them say "turn off guest" as 1st on list.
Personally I have registered users under control now.
I'd not even consider any open guest forum. life really is too short for that pain. (try it, for a month then tell me, on an open www)
There are answers (weak) to the "bad posts" plugins (mod)
here is one of the better spam lists. (hope this link is ok?)
http://www.phpbbhacks.com/forums/stoppin...67553.html
here is my recommendation, if you must have "guests" (non reg. users)
1: Don't.
2: ban all links, period.
3: limit post times. 1 per 15min?
4: put in flood detections. and block long posts.
5: AI word processing. ( finding posts that have bad words, or bad topics. like blue pills or buy shoes, etc.)
there are plugin's for that, but most admins, hate it, due to its deleted valid posts. "false positives"
i hope my posts are more clear, Im no word smith, just and ET (tech retired)
PS: I recommend you try the software first, then post examples of problems, for best help.
for me?
i tired , 5 majors bbs and when in got to mybb , i fell in love.
it has vast depth and features sets built in and is easy to use.
The control panel works very good.
one thing i learned, (hard) is what i can do and not mess up the core.
that is ,what can i add or change, and then survive a next major release.
on this forum, it excels at that.
All the best !
btw, i can't speak for all spam-bots, but my guess, is is they don't give a hoot , about , where your server is , nor what language it's set for, and why would it.?
they have one goal, get in, and post links. or just pure damage. flooding, etc.
it has no rules, it's the antitheses to rules. really.
think of the internet as a white noise generator (or random)
your job is to filter it.
how you do that, is ART. (and some skill)
and point, 2, it's NOT STATIC.
here is 1 spambot linear flow chart. (IBM style 1960)
1: find new bbs via Google analytic's, etc. (they found mine in 1hr flat , are you surprised?)
2: make a list (of BBS to attack)
3: go to each site. (my site blocks their IP's (fails) {some countries, or AOL blocks them at the front end filters, Read AOLs story}
4: hack in to accounts, or better register or better yet, guests posts (if found stay here, it's easy pickings)
5: posts as many advertisements as you can, or just do as much damage as possible (toss coin)
6: jump to 1. (look ma ! no hands?)
the bots have either OCR (optical char, recognition, google it) and can read Captcha's few real humans can read.
or has a list of all questions. and can tells which is which by shapes(human trained) (expert on captcha's)
some countries the bots are humans paid $1 a day to do as much damage as possible. or the verts (sales links).
note, that many sites keep making Captcha's harder to read, making login's impossible for many retired folks.
Can't read 0/O or I/ 1? (how ever mybb is NICE ! great ART !)
Some bots, create email accounts, then flood you 15 days later, time bomb , bots.
this chart above, shows you what you must do to stop them. #3 block is bee's knees.
the hope and dream is to make "Expert systems" for spam IP blocking.
we are at the beginning with this..., I think we can win.