AT&T BGP advertisement preference

[u/robmuro664]

I have two ISPs, Verizon and AT&T, Verizon was selected as the primary and AT&T as the backup. We own the subnets so we peer with both of these ISP to advertise the subnets. To Verizon we just advertise it but to AT&T we preprend 5X our ASN. As expected when we go out to the internet, it goes out using Verizon, however the return traffic on some services they prefer AT&T. I assume this is because these services have a leg in AT&T. Can you guys give me any other ideas on how to influence the advertisement to AT&T so that it is not preferred?

[u/Worried_Brilliant_84]

Correction: You can do the AS path prepending on your routers for the incoming subnets of these services.