Hi all, I have an OpenBSD machine as a router/firewall. It has 4 ethernet interfaces: re0, em0, em1 and em2. All emX -interfaces are connected to the same ADSL box, re0 connects to my home network switch.
My subscription allows me to have 5 public IP addresses, so this way I can fetch 3 of them. 2 of the IPs are binat'ed to two different hosts in my home network, and the third one is a regular nat for the rest of the nodes. Once I got it up and running (with some minor patches to dhclient-script and rc), I faced a new problem with dhclient for which I can't find information from man pages or Google. Before getting to source code I decided to spam you. All interfaces em0, em1 and em2 get a different next hop. I use mpath routing with three default routes, one to each interface. The problem seems to be that the next hop on one of the interfaces (em1) is also used as the dhcp-server-identifier by my ISP for all the three leases (em0, em1, em2). Therefore, also the dhclients on em0 and em2 try to send DHCP renews to that address. But it seems to get routed to em1: May 12 11:25:08 fw dhclient[1864]: DHCPREQUEST on em2 to 88.192.128.1 port 67 May 12 11:25:08 fw dhclient[1864]: send_packet: No route to host May 12 11:25:20 fw dhclient[13007]: DHCPREQUEST on em1 to 88.192.128.1 port 67 May 12 11:25:20 fw dhclient[13007]: DHCPACK from 88.192.128.1 (00:0b:45:b6:ef:c0) May 12 11:25:20 fw dhclient[13007]: bound to 88.192.133.155 -- renewal in 5180 seconds. I wonder why dhclient looks up the routing table instead of preferring the interface its sitting on. Can this be somehow changed (without patching code)? I know this DHCP server is reachable via any of the three interfaces. Maybe I could manually (i.e. in dhclient-script) add mpath routes to this DHCP server's address for each interface? BR, Teemu Rinta-aho
