Hi People, I hope you can shed some light on a problem I am having with freeradius acting as a proxy. As you can see the packet below has a corrupt UDP header ( Checksum: 0x5b10 (incorrect, should be 0x9f2d) ). If I use radtest then the packet is fine and I get authenticated, the problem only occurs when the request is proxied out, all of the packets forwarded to the secondary radius server have the UDP checksum error, I have tried the latest version of freeradius with exactly the same results, so I have gone back to the version supplied with RedHat, on a fresh build. Versions are as follows: radiusd: FreeRADIUS Version 1.0.1, for host , built on Nov 26 2004 at 10:48:39 OpenSSL 0.9.7g 11 Apr 2005 Linux <MY HOST NAME> 2.6.9-5.ELsmp #1 SMP Wed Jan 5 19:30:39 EST 2005 i686 i686 i386 GNU/Linux This is RedHat ES version 4 Please let me know if you need any further information Regards Graham Frame 12 (197 bytes on wire, 197 bytes captured) Arrival Time: Jun 17, 2005 11:19:35.560228000 Time delta from previous packet: 4.660183000 seconds Time since reference or first frame: 111.704161000 seconds Frame Number: 12 Packet Length: 197 bytes Capture Length: 197 bytes Protocols in frame: eth:ip:udp:radius:eap Ethernet II, Src: 00:12:79:3c:9c:61, Dst: 00:00:0c:07:ac:14 Destination: 00:00:0c:07:ac:14 (All-HSRP-routers_14) Source: 00:12:79:3c:9c:61 (HewlettP_3c:9c:61) Type: IP (0x0800) Internet Protocol, Src Addr: XXX.XXX.XXX.XXX (XXX.XXX.XXX.XXX), Dst Addr: XXX.XXX.XXX.XXX (XXX.XXX.XXX.XXX) Version: 4 Header length: 20 bytes Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00) 0000 00.. = Differentiated Services Codepoint: Default (0x00) .... ..0. = ECN-Capable Transport (ECT): 0 .... ...0 = ECN-CE: 0 Total Length: 183 Identification: 0x0005 (5) Flags: 0x04 (Don't Fragment) 0... = Reserved bit: Not set .1.. = Don't fragment: Set ..0. = More fragments: Not set Fragment offset: 0 Time to live: 64 Protocol: UDP (0x11) Header checksum: 0xdfd5 (correct) Source: XXX.XXX.XXX.XXX (XXX.XXX.XXX.XXX) Destination: XXX.XXX.XXX.XXX (XXX.XXX.XXX.XXX) User Datagram Protocol, Src Port: 1814 (1814), Dst Port: radius (1812) Source port: 1814 (1814) Destination port: radius (1812) Length: 163 Checksum: 0x5b10 (incorrect, should be 0x9f2d) Radius Protocol Code: Access Request (1) Packet identifier: 0x1 (1) Length: 155 Authenticator: 0x22840C6BAE7ECB8E4FE8A8A3773B1A08 Attribute value pairs t:User Name(1) l:8, Value:"graham" User-Name: graham t:Framed MTU(12) l:6, Value:1400 t:Called Station Id(30) l:16, Value:"000e.842e.8230" Called-Station-Id: 000e.842e.8230 t:Calling Station Id(31) l:16, Value:"0040.96a7.f8d2" Calling-Station-Id: 0040.96a7.f8d2 t:Service Type(6) l:6, Value:Login(1) Service-Type: Login (1) t:Message Authenticator(80) l:18, Value:C77E1EE1C2A7E98B00E464AB0DB0DE48 t:EAP Message(79) l:34 Extensible Authentication Protocol Code: Response (2) Id: 2 Length: 32 Type: Identity [RFC3748] (1) Identity (27 bytes): graham@test.com t:NAS Port Type(61) l:6, Value:Wireless IEEE 802.11(19) t:NAS Port(5) l:6, Value:1646 t:NAS IP Address(4) l:6, Value:172.23.1.201 Nas IP Address: 172.23.1.201 (172.23.1.201) t:NAS identifier(32) l:8, Value:"ap1200" t:Proxy State(33) l:5, Value:323533