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On Mon, 10 Jan 2005 16:06:11 +0000 Steve Marvell wrote:
Robin Cornelius wrote: Jan 10 16:02:04 desktop pppd[1843]: sent [LCP EchoReq id=0x5 magic=0xa80ee442] Jan 10 16:02:04 desktop pppd[1843]: rcvd [LCP EchoRep id=0x5 magic=0xb3dd2987] Jan 10 16:02:34 desktop pppd[1843]: sent [LCP EchoReq id=0x6 magic=0xa80ee442] Jan 10 16:02:34 desktop pppd[1843]: rcvd [LCP EchoRep id=0x6 magic=0xb3dd2987] Jan 10 16:03:04 desktop pppd[1843]: sent [LCP EchoReq id=0x7 magic=0xa80ee442] Jan 10 16:03:04 desktop pppd[1843]: rcvd [LCP EchoRep id=0x7 magic=0xb3dd2987] Jan 10 16:03:34 desktop pppd[1843]: sent [LCP EchoReq id=0x8 magic=0xa80ee442] Jan 10 16:04:04 desktop pppd[1843]: sent [LCP EchoReq id=0x9 magic=0xa80ee442] Hmmm Can anyone translate that into English? Steve
Quite handy having the Cisco syllabi to hand: "PPP provides a method for encapsulating multi-protocol datagrams over a point-to-point link, and uses the data link layer (layer 2 of the OSI networking model) for testing the connection. Therefore PPP is made up of two sub-protocols: * Link Control Protocol - Used for establishing the point-to-point link. * Network Control Protocol - Used for configuring the various network layer protocols. PPP uses Link Control Protocol (LCP) to negotiate and setup control options on the WAN data link. PPP uses the Network Control Protocol (NCP) component to encapsulate and negotiate options for multiple network layer protocols. The LCP sits on top of the physical layer and is used to establish, configure, and test the data-link connection. PPP also uses LCP to automatically agree upon encapsulation format options such as: * Authentication - Authentication options require that the calling side of the link enter information to help ensure the caller has the network administrator's permission to make the call. Peer routers exchange authentication messages. Two authentication choices are Password Authentication Protocol (PAP) and Challenge Handshake Authentication Protocol (CHAP). * Compression - Compression options increase the effective throughput on PPP connections by reducing the amount of data in the frame that must travel across the link. The protocol decompresses the frame at its destination. Two compression protocols available in Cisco routers are Stacker and Predictor. * Error detection - Error detection mechanisms with PPP enable a process to identify fault conditions. The Quality and Magic Number options help ensure a reliable, loop-free data link. * Multilink - Cisco IOS Release 11.1 and later supports multilink PPP. This alternative provides load balancing over the router interfaces that PPP uses. * PPP Callback - To further enhance security, Cisco IOS Release 11.1 offers callback over PPP. With this LCP option, a Cisco router can act as a callback client or as a callback server. The client makes the initial call, requests that it be called back, and terminates its initial call. The callback router answers the initial call and makes the return call to the client based on its configuration statements. LCP will also do the following: * Handle varying limits on packet size * Detect common misconfiguration errors * Terminate the link * Determine when a link is functioning properly or when it is failing" Now, echo request and replies are often terms associated with either ping or with keepalives. Since PPP uses LCP keepalives to monitor and maintain the connection state, I would hazards a guess that this is what's going on. The id number seems to reflect this too - the reply seems to be (except for the last entry there) acknowledging the request of the same id number. I'm not sure what's happened in the last entry where it's replying to an request that hasn't happened yet. Weird. Anyway, I would also hazard a guess that the "magic" number is a hashed response to ensure that the replies your ISP is expecting *are* coming from you and not from someone intercepting your LCPs. Grant. -- Artificial intelligence is no match for nuratal stidutipy. -- The Mailing List for the Devon & Cornwall LUG Mail majordomo@xxxxxxxxxxxx with "unsubscribe list" in the message body to unsubscribe.