In my earlier post about using the Blocked Sender list, user Eli Polonsky gave us a terrific trick about how to effectively block spam from foreign domains that you would never get any real email from anyway. Here's his tip:
To the person who asked about blocking foreign domains, there is a way that you can block a good deal of them without using up many of your 500 alloted blocks. Here's the hint: if you enter the two last dotted suffixes into your block list, it will block all e-mails with those two last suffixes. For example, if you block co.uk, it will block all e-mails from all domains that end in co.uk. It won't work if you just enter the last suffix (just entering uk won't work), but the last two does work.
I've blocked the following suffixes to greatly reduce foreign domain spam: ac.uk, bk.ru, co.il, co.jp, co.kr, co.nz, co.uk, co.za, com.ar, com.au, com.br, com.cn, com.hk, com.tw, ne.jp, net.au, net.mk, net.pk, net.tr, org.uk. That block all e-mails that come in with those domain suffixes, regardless of the domain prefixes.
Thank for the great tip Eli !
For more information about using the Blocked Sender List, see this post.