The fact that ISA is receiving traffic from an internal IP on the external NIC seems to hint that you have a cable misplaced or a VLAN is broken. Jim Harrison MCP(NT4, W2K), A+, Network+, PCG http://www.microsoft.com/isaserver http://isaserver.org/Jim_Harrison http://isatools.org Read the help, books and articles! ----- Original Message ----- From: "Eric Poole" <EPoole@xxxxxxxxxxxxxxxxxxxx> To: "[ISAserver.org Discussion List]" <isalist@xxxxxxxxxxxxx> Sent: Wednesday, January 14, 2004 11:53 Subject: [isalist] Re: ISA Server detected a spoof attack http://www.ISAserver.org ISA's internal is on the .10 subnet just like the cisco box. ISA's external is on the .2 subnet. The external (2.9) is on a separate vlan, so it's virtually external. "Ethernet adapter Intranet: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : HPNC7781 Gigabit Server Adapter Physical Address. . . . . . . . . : 00-0B-CD-82-2A-45 DHCP Enabled. . . . . . . . . . . : No IP Address. . . . . . . . . . . . : 172.16.10.110 Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : DNS Servers . . . . . . . . . . . : 172.16.10.41 172.18.52.41 Primary WINS Server . . . . . . . : 172.16.10.41 Secondary WINS Server . . . . . . : 172.16.11.41 Ethernet adapter Extranet: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : HPNC7781 Gigabit Server Adapter2 Physical Address. . . . . . . . . : 00-0B-CD-82-2A-6A DHCP Enabled. . . . . . . . . . . : No IP Address. . . . . . . . . . . . : 172.16.2.9 Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : 172.16.2.20 DNS Servers . . . . . . . . . . . : NetBIOS over Tcpip. . . . . . . . : Disabled" _______________________________________________ Eric Poole IS Security Analyst Community Medical Centers 1140 "T" Street, Fresno, California 93721 559-459-6784 (phone) 559-459-2045 (fax) -----Original Message----- From: Jim Harrison [mailto:jim@xxxxxxxxxxxx] Sent: Wednesday, January 14, 2004 11:33 AM To: [ISAserver.org Discussion List] Subject: [isalist] Re: ISA Server detected a spoof attack http://www.ISAserver.org What does the ISA "ipconfig/all" produce? It sounds like ISA doesn't really agree with you about what's internal. Jim Harrison MCP(NT4, W2K), A+, Network+, PCG http://www.microsoft.com/isaserver http://isaserver.org/Jim_Harrison http://isatools.org Read the help, books and articles! ----- Original Message ----- From: "Eric Poole" <EPoole@xxxxxxxxxxxxxxxxxxxx> To: "[ISAserver.org Discussion List]" <isalist@xxxxxxxxxxxxx> Sent: Wednesday, January 14, 2004 10:32 Subject: [isalist] ISA Server detected a spoof attack http://www.ISAserver.org I'm getting these about every half hour from our internal Cisco Works box (172.16.10.168). The 2.9 address is the ISA external NIC that is routed through our PIX. Any ideas? "ISA Server detected a spoof attack from Internet Protocol (IP) address 172.16.10.168. A spoof attack occurs when an IP address that is not reachable via the interface on which the packet was received. If logging for dropped packets is set, you can view details in the packet filter log." Here's a sample from the packet filter log. "1/13/2004, 20:43:17, 172.16.10.168, 172.16.2.9, ICMP, 8, 0, -, BLOCKED, 172.16.2.9, 45 00 00 3c 20 74 00 00 7f 01 b6 7b ac 10 0a a8 ac 10 02 09, 08 00 a1 b6 04 00 77 6e ad ad ad ad ad ad ad ad ad ..." _______________________________________________ Eric Poole IS Security Analyst Community Medical Centers 1140 "T" Street, Fresno, California 93721 559-459-6784 (phone) 559-459-2045 (fax) ------------------------------------------------------ List Archives: http://www.webelists.com/cgi/lyris.pl?enter=isalist ISA Server Newsletter: http://www.isaserver.org/pages/newsletter.asp ISA Server FAQ: http://www.isaserver.org/pages/larticle.asp?type=FAQ ------------------------------------------------------ Other Internet Software Marketing Sites: Leading Network Software Directory: http://www.serverfiles.com No.1 Exchange Server Resource Site: http://www.msexchange.org Windows Security Resource Site: http://www.windowsecurity.com/ Network Security Library: http://www.secinf.net/ Windows 2000/NT Fax Solutions: http://www.ntfaxfaq.com ------------------------------------------------------ You are currently subscribed to this ISAserver.org Discussion List as: jim@xxxxxxxxxxxx To unsubscribe send a blank email to $subst('Email.Unsub') ------------------------------------------------------ List Archives: http://www.webelists.com/cgi/lyris.pl?enter=isalist ISA Server Newsletter: http://www.isaserver.org/pages/newsletter.asp ISA Server FAQ: http://www.isaserver.org/pages/larticle.asp?type=FAQ ------------------------------------------------------ Other Internet Software Marketing Sites: Leading Network Software Directory: http://www.serverfiles.com No.1 Exchange Server Resource Site: http://www.msexchange.org Windows Security Resource Site: http://www.windowsecurity.com/ Network Security Library: http://www.secinf.net/ Windows 2000/NT Fax Solutions: http://www.ntfaxfaq.com ------------------------------------------------------ You are currently subscribed to this ISAserver.org Discussion List as: epoole@xxxxxxxxxxxxxxxxxxxx To unsubscribe send a blank email to $subst('Email.Unsub') ------------------------------------------------------ List Archives: http://www.webelists.com/cgi/lyris.pl?enter=isalist ISA Server Newsletter: http://www.isaserver.org/pages/newsletter.asp ISA Server FAQ: http://www.isaserver.org/pages/larticle.asp?type=FAQ ------------------------------------------------------ Other Internet Software Marketing Sites: Leading Network Software Directory: http://www.serverfiles.com No.1 Exchange Server Resource Site: http://www.msexchange.org Windows Security Resource Site: http://www.windowsecurity.com/ Network Security Library: http://www.secinf.net/ Windows 2000/NT Fax Solutions: http://www.ntfaxfaq.com ------------------------------------------------------ You are currently subscribed to this ISAserver.org Discussion List as: jim@xxxxxxxxxxxx To unsubscribe send a blank email to $subst('Email.Unsub')