diff options
Diffstat (limited to 'man7/arp.7')
| -rw-r--r-- | man7/arp.7 | 28 |
1 files changed, 14 insertions, 14 deletions
@@ -6,7 +6,7 @@ .\" Modified June 1999 Andi Kleen .\" $Id: arp.7,v 1.10 2000/04/27 19:31:38 ak Exp $ .\" -.TH arp 7 2023-07-15 "Linux man-pages 6.05.01" +.TH arp 7 2023-10-31 "Linux man-pages 6.7" .SH NAME arp \- Linux ARP kernel module. .SH DESCRIPTION @@ -17,7 +17,7 @@ and IPv4 protocol addresses on directly connected networks. The user normally doesn't interact directly with this module except to configure it; instead it provides a service for other protocols in the kernel. -.PP +.P A user process can receive ARP packets by using .BR packet (7) sockets. @@ -30,7 +30,7 @@ The ARP table can also be controlled via on any .B AF_INET socket. -.PP +.P The ARP module maintains a cache of mappings between hardware addresses and protocol addresses. The cache has a limited size so old and less @@ -42,7 +42,7 @@ be directly manipulated by the use of ioctls and its behavior can be tuned by the .I /proc interfaces described below. -.PP +.P When there is no positive feedback for an existing mapping after some time (see the .I /proc @@ -65,7 +65,7 @@ If that fails too, it will broadcast a new ARP request to the network. Requests are sent only when there is data queued for sending. -.PP +.P Linux will automatically add a nonpermanent proxy arp entry when it receives a request for an address it forwards to and proxy arp is enabled on the receiving interface. @@ -77,7 +77,7 @@ sockets. They take a pointer to a .I struct arpreq as their argument. -.PP +.P .in +4n .EX struct arpreq { @@ -89,14 +89,14 @@ struct arpreq { }; .EE .in -.PP +.P .BR SIOCSARP ", " SIOCDARP " and " SIOCGARP respectively set, delete, and get an ARP mapping. Setting and deleting ARP maps are privileged operations and may be performed only by a process with the .B CAP_NET_ADMIN capability or an effective UID of 0. -.PP +.P .I arp_pa must be an .B AF_INET @@ -121,7 +121,7 @@ ATF_NETMASK:Use a netmask ATF_DONTPUB:Don't answer .TE .RE -.PP +.P If the .B ATF_NETMASK flag is set, then @@ -272,13 +272,13 @@ changed in Linux 2.0 to include the .I arp_dev member and the ioctl numbers changed at the same time. Support for the old ioctls was dropped in Linux 2.2. -.PP +.P Support for proxy arp entries for networks (netmask not equal 0xffffffff) was dropped in Linux 2.2. It is replaced by automatic proxy arp setup by the kernel for all reachable hosts on other interfaces (when forwarding and proxy arp is enabled for the interface). -.PP +.P The .I neigh/* interfaces did not exist before Linux 2.2. @@ -286,20 +286,20 @@ interfaces did not exist before Linux 2.2. Some timer settings are specified in jiffies, which is architecture- and kernel version-dependent; see .BR time (7). -.PP +.P There is no way to signal positive feedback from user space. This means connection-oriented protocols implemented in user space will generate excessive ARP traffic, because ndisc will regularly reprobe the MAC address. The same problem applies for some kernel protocols (e.g., NFS over UDP). -.PP +.P This man page mashes together functionality that is IPv4-specific with functionality that is shared between IPv4 and IPv6. .SH SEE ALSO .BR capabilities (7), .BR ip (7), .BR arpd (8) -.PP +.P RFC\ 826 for a description of ARP. RFC\ 2461 for a description of IPv6 neighbor discovery and the base algorithms used. |