[tor-talk] Tor has started opening x2 udp ports

Sun Dec 9 14:41:08 UTC 2012

On Sat, Dec 08, 2012 at 11:19:39PM -0800, redrs at riseup.net wrote 1.2K bytes in 33 lines about:
: I've been running a Tor relay for a couple of years now and I've never
: seen this before.. .

Thanks for running a relay!

: udp    0    0 *:42883                 *:*                   1406/tor
: udp    0    0 *:13435                 *:*                   1406/tor

Fairly confident these are for dns resolution. Someone else asked this as well, so I did some stracing:

3985  stat("/etc/resolv.conf", {st_mode=S_IFREG|0644, st_size=75, ...}) = 0
3985  open("/etc/resolv.conf", O_RDONLY|O_CLOEXEC) = 21
3985  fstat(21, {st_mode=S_IFREG|0644, st_size=75, ...}) = 0
3985  read(21, "# Generated by NetworkManager\nna"..., 75) = 75
3985  socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 22
3985  fcntl(22, F_SETFD, FD_CLOEXEC)    = 0
3985  fcntl(22, F_SETFL, O_RDONLY|O_NONBLOCK) = 0
3985  connect(22, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("127.0.0.1")}, 16) = 0
3985  epoll_ctl(3, EPOLL_CTL_ADD, 22, {EPOLLIN, {u32=22, u64=22}}) = 0
3985  socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 26
3985  fcntl(26, F_SETFD, FD_CLOEXEC)    = 0
3985  fcntl(26, F_SETFL, O_RDONLY|O_NONBLOCK) = 0
3985  connect(26, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.11.1")}, 16) = 0
3985  epoll_ctl(3, EPOLL_CTL_ADD, 26, {EPOLLIN, {u32=26, u64=26}}) = 0

which results in:

udp        0      0 127.0.0.1:38241         127.0.0.1:53            ESTABLISHED 3985/tor
udp        0      0 192.168.11.254:41549    192.168.11.1:53         ESTABLISHED 3985/tor

udp ports 38421 and 41549 stay open as long as that tor process is running.

This is on a non-exit relay in my VM environment.

-- 
Andrew
http://tpo.is/contact
pgp 0x6B4D6475