Palo Alto Networks : Firewall Loopback interfaces

In a dual-homed network infrastructure, loopback interfaces are a very valuable configuration option on Palo Alto firewalls. Cisco folk may be more familiar with the use of loopback interfaces, so this article gives a very quick look at some of the uses of a loopback interface in a Palo Alto firewall deployment. The most usedul … Continue reading Palo Alto Networks : Firewall Loopback interfaces

Email Error: 450 Client host rejected

A couple of our clients sometimes have issues when sending email, with a returned non-delivery report stating the following: Peer server rejected email: 450 Client host rejected: 'cannot find your hostname' It turns out this is a very strict check (usually performed by postfix), that is controlled via the directive reject_unknown_client_hostname in the postfix configuration. The documentation … Continue reading Email Error: 450 Client host rejected