Networking

Fedora networking is done with the following components:

• Kernel
• GLIBC
• NetworkManager
• ISC DHCP

Networking concepts and configuration

• Ethernet
• IPv4 and IPv6 addressing
• IPv4 and IPv6 routing
• Ethernet bridging
• Ethernet bonding/teaming
• TCP, UDP and ICMP NAT
• Traffic control
• Tunneling

Networking problems

Only platform bugs that can influence various application and/or the overall behavior of the system belong here.

Kernel

• Bridge: Adding first interface after setting MAC address changes the MAC address
• IPv4: Kernel can't store DHCP lifetime and cannot mark IPv6 addresses dynamic (in the DHCP sense)
• IPv6: Kernel ignores RA router preference
• IPv6: Tempaddr cycling breaks TCP connections prematurely
• IPv6: Kernel doesn't cache RDNSS and DNSSL
• IPv6: Kernel doesn't provide default route information when defrtr is disabled
• IPv6: Kernel doesn't provide prefix route information when pinfo is disabled

libnl

• rtnl_link_bond_add() succeeds when device already exists
• rtnl_link_bridge_add() and rtnl_link_vlan_add missing

iproute

• iproute won't distinguish bridges and bonds
• iproute won't show vlan id

GLIBC

• IPv4: getaddrinfo("127.0.0.1", ...) fail with some AI_ADDRCONFIG configurations
• IPv6: Fedora 808147 - getaddrinfo("::1", ...) fails with some configurations of AI_ADDRCONFIG
• IPv6: getaddrinfo("fe80::1234:56ff:fe78:90%eth0", ...) also fails as above
• IPv6: GLIBC's nsswitch doesn't support overriding getaddrinfo which is requred to resolve link-local IPv6 addresses
• DNS: getaddrinfo doesn't support SRV records

dhclient

• Fixed: dhclient fails with large values of dhcp-renawal-time, notably the infinity (0xffffffff) value
• People say that dhclient exchange is slow, especially on wireless (I can't reproduce)

Avahi

• Avahi's nss-mdns returns link-local IPv6 addresses without scope_id and applications fail to connect
• Avahi's IPv6 support is disabled by default (this has been resolved in the past)

NetworkManager

• Various bugs in NetworkManager

Testing tools

• ping doesn't support IPv6 (you have to use ping6)