Help on Comodo Dragon firewall security ?

[Pankhu]

I just started using the latest version of Comodo firewal. It showed a huge amt of updation after starting, I think its virus definition of something. Its size is about 160 MB. I avoided it till now due to slow and limited internet (I will download that update later when convenient, until then the firewal is working alright). I guess, It won't scan things for virus until I fully update the file. Tell me whats its purpose?

There was also an option of diverting DNS to a Comodo DNS (perhaps filter loopback traffic to a new local IP) to make them work faster or something. Is it safe? Whats the purpose?

What settings on the level of security I should keep? Can you help me on basics for settings for general purpose? Thanks
Rick, I see, I disabled antivirus of comodo permanently now bec I already have Avast latest one. I heard that Comodo firewal is best. So I should rather use only the firewall of comodo. It also gave me browser which is a version of Chrome. I don't use that.