The IP Tab has four sub-tabs which display IP Statistics, the IP Address Table, the IP Route Table and the IP Net-to-Media Table. These sub-tabs are detailed below.
Forwarding: This indicates whether the router is acting as an IP gateway with respect to the forwarding of datagrams received by, but not addressed to, it. IP gateways forward datagrams. IP hosts do not (except those source-routed via the host).
DefaultTTL: The default value inserted into the Time-To-Live field of the IP header of datagrams originated at the router, whenever a TTL value is not supplied by the transport layer protocol.
InReceives: The total number of input datagrams received from interfaces, including those received in error.
InHdrErrors: The number of input datagrams discarded due to errors in their IP headers, including bad checksums, version number mismatch, other format errors, time-to-live exceeded, errors discovered in processing their IP options, etc.
ForwDatagrams: The number of input datagrams for which the router was not their final IP destination, as a result of which an attempt was made to find a route to forward them to that final destination. Where the router does not act as IP Gateway, this counter will include only those packets which were Source-Routed via it, and the Source-Route option processing was successful.
InUnknownProtos: The number of locally-addressed datagrams received successfully but discarded because of an unknown or unsupported protocol.
InDiscards: The number of input IP datagrams for which no problems were encountered to prevent their continued processing, but which were discarded (eg, for lack of buffer space). Note that this counter does not include any datagrams discarded while awaiting re-assembly.
InDelivers: The total number of input datagrams successfully delivered to IP user-protocols (including ICMP).
OutRequests: The total number of IP datagrams which local IP user-protocols (including ICMP) supplied to IP in requests for transmission. Note that this counter does not include any datagrams counted in ForwDatagrams.
OutDisards: The number of output IP datagrams for which no problem was encountered to prevent their transmission to their destination, but which were discarded (eg, for lack of buffer space). Note that this counter would include datagrams counted in ForwDatagrams if any such packets met this (discretionary) discard criterion.
OutNoRoutes: The number of IP datagrams discarded because no route could be found to transmit them to their destination. Note that this counter includes any packets counted in ForwDatagrams which meet this "no-route" criterion. Note that this includes any datagrams which a host cannot route because all of its default gateways are down.
ReasmTimeout: The maximum number of seconds which received fragments are held while they are awaiting reassembly at the router.
ReasmReqds: The number of IP fragments received which needed to be reassembled at the router.
ReasmOKs: The number of IP datagrams successfully re-assembled.
ReasmFails: The number of failures detected by the IP re-assembly algorithm (for whatever reason: timed out, errors, etc). Note that this is not necessarily a count of discarded IP fragments since some algorithms (notably the algorithm in RFC 815) can lose track of the number of fragments by combining them as they are received.
FragOKs: The number of IP datagrams that have been successfully fragmented at the router.
FragFails: The number of IP datagrams that have been discarded because they needed to be fragmented at this entity but could not be because, for example, their Don't Fragment flag was set.
FragCreates: The number of IP datagram fragments that have been generated as a result of fragmentation at the router.
RoutingDiscards: The number of routing entries which were chosen to be discarded even though they were valid. One possible reason for discarding such an entry could be to free-up buffer space for other routing entries.
The Address Table contains the router's IP address information. Each entry in the table lists:
IP address: The IP address to which this entry's addressing information pertains.
Interface: The index value which uniquely identifies the interface to which this entry is applicable. The interface identified by this index is the same as the index shown in the Interfaces Tab in square brackets after the interface name.
Subnet mask: The subnet mask associated with the IP address of this entry. The value of the mask is an IP address with all the network bits set to 1 and all the hosts bits set to 0.
Broadcast: The value of the least-significant bit in the IP broadcast address used for sending datagrams on the (logical) interface associated with the IP address of this entry. For example, when the Internet standard all-ones broadcast address is used, the value will be 1. This value applies to both the subnet and network broadcasts addresses used by the entity on this (logical) interface.
ReasmMaxSize: The size of the largest IP datagram which this entity can re-assemble from incoming IP fragmented datagrams received on this interface.
The "Copy table" button will copy the contents of this table to the clipboard. The "Save table" button allows you to save the contents of the table to a file.
The IP routing table contains an entry for each route presently known to the router Each entry in the table lists:
Destination: The destination IP address of this route. An entry with a value of 0.0.0.0 is considered a default route. Multiple routes to a single destination can appear in the table, but access to such multiple entries is dependent on the table-access mechanisms defined by the network management protocol in use.
Interface: The index value which uniquely identifies the local interface through which the next hop of this route should be reached. The interface identified by a particular value of this index is the same interface as identified in the Interfaces Tab in square brackets after the interface name.
NextHop: The IP address of the next hop of this route. In the case of a route bound to an interface which is realized via a broadcast media, the value of this field is the agent's IP address on that interface.
Type: The type of route. The valid types are: other - none of the following; invalid - an invalidated route; direct - route to directly to a connected (sub-)network; and indirect - route to a non-local host/network/sub-network.
Proto: The routing mechanism via which this route was learned. The valid types are: other - none of the following; local - non-protocol information (eg, manually configured); netmgmt - entries set via a network management protocol; icmp - obtained via ICMP (eg, Redirect); and the following gateway routing protocols: egp, ggp, hello, rip, is-is, es-is, ciscoIgrp, bbnSpfIgp, ospf, bgp.
Age: The number of seconds since this route was last updated or otherwise determined to be correct. Note that no semantics of "too old" can be implied except through knowledge of the routing protocol by which the route was learned.
Mask: Indicates the mask to be logical-ANDed with the destination address before being compared to the value in the Destination field. If the value of the Destination is 0.0.0.0 (a default route), then the mask value is also 0.0.0.0. It should be noted that all IP routing subsystems implicitly use this mechanism.
Metric 1-5: The primary (1) and alternative (2-5) routing metrics for this route. The semantics of this metric are determined by the routing-protocol specified in the route's Proto value.
Info: A reference to MIB definitions specific to the particular routing protocol which is responsible for this route, as determined by the value specified in the route's Proto value.
The "Copy table" button will copy the contents of this table to the clipboard. The "Save table" button allows you to save the contents of the table to a file.
The IP Address Translation table used for mapping from IP addresses to physical addresses. Each entry in the list contains:
Interface: The interface on which this entry's equivalence is effective. The interface number identified here is same interface number identified in the Interfaces Tab in square brackets after the interface name.
Physical address: The media-dependent "physical" address.
Net address: The IP address corresponding to the media-dependent "physical" address.
Type: The valid types are: other - none of the following; invalid - an invalidated mapping; dynamic and static.
The "Copy table" button will copy the contents of this table to the clipboard. The "Save table" button allows you to save the contents of the table to a file.
The "Help" button will display the context-sensitive help file for this tab. Pressing F1 at any time will also display the context-sensitive help file.
The "Update" button will update the information displayed in this tab.