i had 550 5.7.1 Unable to relay issue on exchange 2007. As per ID ID:22678110. i got resolved the issue. But now i am not getting lot of spam mails. As per above given id i have modified the edge external receiver connector as described below.
. log on to the edge server go to the properties of the Default Ext edge receive connector. click the Permission group tab check Exchange Servers tick box which is currently unticked. click Apply click the authentication tab Untick Enable Domain Security (Mutual auth TLS) Untick "Exchange server authentication" Tick "Externally Secured (for e.g. IPSEC)" check box. click Apply
Please help me to stop this spam.