|ENC(4)||AerieBSD 1.0 Refernce Manual||ENC(4)|
pass in on enc0 proto ipencap from 172.25.0.45 to 220.127.116.11 \e keep state (if-bound)
Secondly, the enc interface does not directly support bandwidth control via pf(4) queueing. Instead, IPsec packets must be tagged and the tagged packets are assigned to queues. ipsec.conf(5) provides an example of tag-based queueing and further information on packet tagging. Finally, the use of translation rules to map and redirect network traffic requires some care. Packets destined to be IPsec processed are seen by the filer/translation engine twice, both before and after being IPsec processed. If a packet's translated address on the way back fails to match an existing IPsec flow, from the translated address to the original source address, it will be discarded by the filter. It is best to avoid this situation where possible, though a flow may be explicitly created to work around it. As noted above, tcpdump(8) may be invoked on the enc interface to see packets prior to encapsulation and after decapsulation. For example:
# tcpdump -envps 1500 -i enc0 -l | grep 10.0.0.33 tcpdump: WARNING: enc0: no IPv4 address assigned tcpdump: listening on enc0, link-type ENC 15:05:08.934708 (authentic,confidential): SPI 0x6bcac587: \e 172.25.0.45 \*(Gt 18.104.22.168: 10.9.9.28.7001 \*(Gt 10.0.0.33.7000: \e [udp sum ok] udp 52 (ttl 64, id 5672, len 80) \e (ttl 64, id 30009, len 100, bad cksum 0!) 15:05:09.063517 (authentic,confidential): SPI 0x4b70c05a: \e 22.214.171.124 \*(Gt 172.25.0.45: 10.0.0.33.7000 \*(Gt 10.9.9.28.7001: \e [udp sum ok] udp 156 (ttl 63, id 14880, len 184) \e (ttl 51, id 19689, len 204)
The packets above show (for each direction): date, ESP (not AH), SPI, direction, and encapsulated part. The first packet is headed from 172.25.0.45 to 126.96.36.199 and the encapsulated part from 10.9.9.28 to 10.0.0.33. Negotiations can be watched on the physical interface too:
# tcpdump -envps 1500 -i wi0 port 500 or port 4500 tcpdump: listening on wi0, link-type EN10MB 15:15:58.188747 0:2:6f:3a:3f:3e 0:10:f3:3:bd:8a 0800 226: \e 172.25.0.45.500 \*(Gt 188.8.131.52.500: [udp sum ok] \e [...] attribute ENCRYPTION_ALGORITHM = AES_CBC attribute HASH_ALGORITHM = SHA attribute AUTHENTICATION_METHOD = RSA_SIG attribute GROUP_DESCRIPTION = MODP_1024 attribute LIFE_TYPE = SECONDS attribute LIFE_DURATION = 3600 attribute KEY_LENGTH = 128 [...] 15:15:59.080058 0:10:f3:3:bd:8a 0:2:6f:3a:3f:3e 0800 226: \e 184.108.40.206.500 \*(Gt 172.25.0.45.500: [udp sum ok] \e [...] attribute ENCRYPTION_ALGORITHM = AES_CBC attribute HASH_ALGORITHM = SHA attribute AUTHENTICATION_METHOD = RSA_SIG attribute GROUP_DESCRIPTION = MODP_1024 attribute LIFE_TYPE = SECONDS attribute LIFE_DURATION = 3600 attribute KEY_LENGTH = 128 [...]
The attribute lines for the negotiation must match.
|AerieBSD 1.0 Reference Manual||August 26 2008||ENC(4)|