DNAS ISN'T detecting mod chips. All modchips are 100% compatible with online gaming, I self use the messiah 1(one of the first mod chips out, before online was avalaible for PS2), without any troubles.I am 100% sure that the DNAS doesn't check if u are using a modchip, because a messiah 1 can't be deactivated, and I'm using one without any problems. It only bans u if it finds out that you are using a invalid dnas key, because every online game contains it unique dnas key, so if you copy yours' friends disc and you go online together, dnas will see that there are two same dnas keys online and you both will be banned.But if make a backup of your original, dnas will give your back-up a invalid dnas key, so you will also be banned if you are playing with a legal back-up!!!The only way to play a legal back-up is to use a tool, that finds out wath the valid dnas key is for your copy (answer for ronaldo9_r9).And remember if you get banned, you will banned for good, because they ban your serial number of the PS2, and the screen will only give an error, it doesn't say that u are banned for using a illegal copy. I hope that this answers everybody's questions.
*Are their people here that have tried to go online with a backup and then dnas gives you a error (ronaldo9_r9), but after this you are not banned, so after that you can play your original copy online???