Package: dhcp3-relay Severity: important Running version 3.0.1-2 of dhcp3-relay, I needed to run a development DHCP server alongside it. I decided to bind the dhcp server to the local loopback interface (lo) and configure dhcp3-relay with: SERVERS="127.0.0.1" INTERFACES="eth0.95 eth0.96 eth0.97" OPTIONS="-m discard"
The packets arrive okay, but when dhcp3-relay passes them on the udp checksum that //leaves// on the udp packet is incorrect. If you look at the attached packet capture (dhcp-fail.dump) you can see the packets coming in okay, but then when dhcp3-relay passes them on the udp checksum is corrupt. I first tested with a 127.0.0.1<->127.0.0.1 setup and when that failed I thought about trying to 'real' public IP's incase it was some strange loopback issue. I got the exact same problem. :( Its only when the source address matches the destination address, it seems, that the checksum is incorrect calculated. I have attached a capture (dhcp-good.dump) of it behaving correctly when its relaying to a non-local dhcp server on another computer. Okay, its extremely unlikely that someone would want to run a relay on the same machine as the dhcp server it-self but in a development environment is saves 'borrowing' another computer; it also points to a slight issue in the underlying checksum generator[1] which should be corrected. Meanwhile the dhcp server keeps filling up the syslog with: Feb 16 14:07:07 troll dhcpd: 5 bad udp checksums in 5 packets Feb 16 14:07:24 troll dhcpd: 5 bad udp checksums in 5 packets Feb 16 14:07:33 troll dhcpd: 5 bad udp checksums in 5 packets Feb 16 14:07:53 troll dhcpd: 5 bad udp checksums in 5 packets Feb 16 14:08:44 troll dhcpd: 5 bad udp checksums in 5 packets Feb 16 14:08:57 troll dhcpd: 5 bad udp checksums in 5 packets Feb 16 14:09:23 troll dhcpd: 5 bad udp checksums in 5 packets Which is correct, as the checksum is indeed incorrect. Cheers Alex [1] I'm assuming that the dhcp relay server opens a raw socket and so generates its own udp checksum? -- System Information (altered to reflect settings on actual server): Debian Release: testing/unstable APT prefers stable Architecture: i386 (i686) Shell: /bin/sh linked to /bin/bash Kernel: Linux 2.6.15-ck1 Locale: LANG=C, LC_CTYPE=C (charmap=ANSI_X3.4-1968) -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]