# Cannot connect to server, errno=111 **URL:** \ **Category:** Users/Site Administrators\ **Created:** [May 27, 2020, 12:27pm UTC](https://community.openpbs.org/t/cannot-connect-to-server-errno-111/2141 "2020-05-27T12:27:25Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![akpc](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@akpc](https://community.openpbs.org/u/akpc)\ **Post date:** [May 27, 2020, 12:27pm UTC](https://community.openpbs.org/t/cannot-connect-to-server-errno-111/2141/1 "2020-05-27T12:27:25Z")
Hi, I am having trouble debugging connection to computational nodes. I tried everything in the similar issues, but I can’t locate the problem Here are the symptoms. First `pbs-hostn` and `pbsnodes` both show the nodes ```auto $pbs_hostn -v vt001 primary name: vt001 (from gethostbyname()) aliases: -none- address length: 4 bytes address: 192.168.20.1 (18131136 dec) name: vt001 ``` ```auto $pbsnodes -a vt001 Mom = vt001 ntype = PBS state = free pcpus = 96 resources_available.arch = linux resources_available.host = vt001 resources_available.mem = 394907120kb resources_available.ncpus = 96 resources_available.vnode = vt001 resources_assigned.accelerator_memory = 0kb resources_assigned.hbmem = 0kb resources_assigned.mem = 0kb resources_assigned.naccelerators = 0 resources_assigned.ncpus = 0 resources_assigned.vmem = 0kb resv_enable = True sharing = default_shared .. ``` However when I use `pbsnodes -l -s vt001` it fails ```auto $pbsnodes -l -s vt001 Connection refused pbsnodes: cannot connect to server vt001, error=111 ``` I tried to use strace to locate the problem but I didn’t know how to proceed ```auto $strace pbsnodes -l -s vt001 ...... fstat(3, {st_mode=S_IFREG|0644, st_size=19183, ...}) = 0 read(3, "# Network services, Internet sty"..., 4096) = 4096 read(3, "1/tcp\t\tClearcase\nclearcase\t371/u"..., 4096) = 4096 read(3, "\t1812/tcp\nradius\t\t1812/udp\nradiu"..., 4096) = 4096 read(3, "\t# users & groups database\nafs3-"..., 4096) = 4096 read(3, "/tcp\t\t\t# french minitel\nxtelw\t\t1"..., 4096) = 2799 read(3, "", 4096) = 0 close(3) = 0 openat(AT_FDCWD, "/etc/pbs.conf", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=177, ...}) = 0 read(3, "PBS_SERVER=feynman\nPBS_START_SER"..., 4096) = 177 read(3, "", 4096) = 0 close(3) = 0 openat(AT_FDCWD, "/etc/pbs.conf", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=177, ...}) = 0 read(3, "PBS_SERVER=feynman\nPBS_START_SER"..., 4096) = 177 read(3, "", 4096) = 0 close(3) = 0 socket(AF_INET, SOCK_STREAM, IPPROTO_IP) = 3 socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0) = 4 connect(4, {sa_family=AF_UNIX, sun_path="/var/run/nscd/socket"}, 110) = -1 ENOENT (No such file or directory) close(4) = 0 socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0) = 4 connect(4, {sa_family=AF_UNIX, sun_path="/var/run/nscd/socket"}, 110) = -1 ENOENT (No such file or directory) close(4) = 0 stat("/etc/resolv.conf", {st_mode=S_IFREG|0644, st_size=590, ...}) = 0 openat(AT_FDCWD, "/etc/host.conf", O_RDONLY|O_CLOEXEC) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=92, ...}) = 0 read(4, "# The \"order\" line is only used "..., 4096) = 92 read(4, "", 4096) = 0 close(4) = 0 futex(0x7f6ed0ac4ba4, FUTEX_WAKE_PRIVATE, 2147483647) = 0 openat(AT_FDCWD, "/etc/resolv.conf", O_RDONLY|O_CLOEXEC) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=590, ...}) = 0 read(4, "# This file is managed by man:sy"..., 4096) = 590 read(4, "", 4096) = 0 close(4) = 0 uname({sysname="Linux", nodename="feynman", ...}) = 0 openat(AT_FDCWD, "/etc/hosts", O_RDONLY|O_CLOEXEC) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=517, ...}) = 0 read(4, "127.0.0.1\tlocalhost\n127.0.1.1\tub"..., 4096) = 517 read(4, "", 4096) = 0 close(4) = 0 connect(3, {sa_family=AF_INET, sin_port=htons(15001), sin_addr=inet_addr("192.168.20.1")}, 16) = -1 ECONNREFUSED (Connection refused) close(3) = 0 dup(2) = 3 fcntl(3, F_GETFL) = 0x2 (flags O_RDWR) fstat(3, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 4), ...}) = 0 write(3, "Connection refused\n", 19Connection refused ) = 19 close(3) = 0 write(2, "pbsnodes: cannot connect to serv"..., 52pbsnodes: cannot connect to server vt001, error=111 ) = 52 exit_group(1) = ? +++ exited with 1 +++ ``` In the node, I checked if the pbs\_mom is running by ```auto $ /etc/init.d/pbs status pbs_mom is pid 2332 ``` * * * I proceeded to check the opened ports ```auto admin@server:$sudo lsof -i -P -n | grep LISTEN pbs_comm 26877 root 13u IPv4 9665789 0t0 TCP *:17001 (LISTEN) pbs_sched 26892 root 4u IPv4 9663067 0t0 TCP *:15004 (LISTEN) pbs_serve 27095 root 8u IPv4 9649094 0t0 TCP *:15001 (LISTEN) admin@vt001:$sudo lsof -i -P -n | grep LISTEN pbs_mom 82765 root 5u IPv4 3442317 0t0 TCP *:15002 (LISTEN) pbs_mom 82765 root 6u IPv4 3442318 0t0 TCP *:15003 (LISTEN) ``` Many thanks ---
**Author:** ![akpc](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@akpc](https://community.openpbs.org/u/akpc)\ **Post date:** [May 27, 2020, 1:41pm UTC](https://community.openpbs.org/t/cannot-connect-to-server-errno-111/2141/2 "2020-05-27T13:41:10Z")
I was asking the wrong question, that I found out. There is only one ‘server’. The Computational node is ‘MoM’ The software was doing exactly what it supposed to do.