mail forwarding problem with 2nd redlink

[Guest]

[yogesh]

hi

i am using 2 red interface 1st is tata broadband for browsing and 2nd airtel lease line for mail server and vpn server
i am not using smtpproxy, mail coming  through port forwarding feature every thing goes smooth but my problem is this
if i active tata link my all mail goes through tata but it is black listed ip and other domain not to received the mails and bounced back all the mail if i active airtel lease line every think works fine but my browsing through airtel lease line.

plz tell me howto i solved the problem i want tata only for browsing and airtel only mail server. my mail server configure on DMZ interface.

reply ASAP

thank you very much