Deep practical knowledge of legacy Gen 2/Gen 3 Palo Alto hardware, including PA-3000 and PA-5000 series platforms, legacy CLI, hardware troubleshooting, and line-card replacements. Advanced understanding of BGP, OSPF, IPSec VPNs, NAT, TLS/SSL, mutual TLS (mTLS), HTTP, SAML, OAuth, OCSP revocation, DoD PKI, Kerberos, LDAP, and Active Directory.