To be on the safe side, I would register both (in your case, as if I were you…):
srv-1.toto.info IN A 11.22.33.44 (This could be a cname to mail.toto.info)
mail.toto.info IN A 11.22.33.44
toto.info IN MX 10 mail.toto.info (Note, here it’s the full domain on the left, not a “host”)
This can be done at your normal DNS Registrar/Provider (Gandi?).
I would additionally register
11.22.33.44 IN PTR mail.toto.info
This must be registered with your ISP Provider (Teksawy.com?). They “own” that IP…
This is one of the most important things, for a decent mail service and a good IP reputation!
A good mail server can have a FQDN - but for all relevant mail aspects, it should show up as mail.domain.com - as that domains logical main mail server! (Yours should always give mail.toto.info ).
Global DNS propagation can take from 1-2 hours (very fast) to 24-36 hours (very slow)…
My 2 cents
Andy