telnet 접속시 xterm 창이 안떠요 [1]

집에서 PC로 학교에 있는 리눅스에 접속하고 있습니다.
원래는 SSH 로 접속이 잘 되고 있었는데 어느날부터인가 port22 연결이 안된다는 메시지와 함께 접속이 안됩니다.
갑자기 안되는 이유를 찾지 못한 채 telnet 으로 접속을 시도했는데 접속이 되는 듯 한데 xterm 창이 뜨지 않습니다.
<원격 실행 결과창 보여주기> 옵션을 지정해놓으면
다음과 같은 메시지가 뜹니다.
-----------------------------------------------------
Telnet Server
login: ysghim
Password:
Last login: Sat Nov 30 23:38:20 from 121.165.37.220


[ysghim@sanha ysghim]$
[ysghim@sanha ysghim]$
[ysghim@sanha ysghim]$ /
[ysghim@sanha ysghim]$ /
[ysghim@sanha ysghim]$ /u
[ysghim@sanha ysghim]$ /u
[ysghim@sanha ysghim]$ /us
[ysghim@sanha ysghim]$ /us
[ysghim@sanha ysghim]$ /usr
[ysghim@sanha ysghim]$ /usr
[ysghim@sanha ysghim]$ /usr/
[ysghim@sanha ysghim]$ /usr/
[ysghim@sanha ysghim]$ /usr/b
[ysghim@sanha ysghim]$ /usr/b
[ysghim@sanha ysghim]$ /usr/bi
[ysghim@sanha ysghim]$ /usr/bi
[ysghim@sanha ysghim]$ /usr/bin
[ysghim@sanha ysghim]$ /usr/bin
[ysghim@sanha ysghim]$ /usr/bin/
[ysghim@sanha ysghim]$ /usr/bin/
[ysghim@sanha ysghim]$ /usr/bin/X
[ysghim@sanha ysghim]$ /usr/bin/X
[ysghim@sanha ysghim]$ /usr/bin/X1
[ysghim@sanha ysghim]$ /usr/bin/X1
[ysghim@sanha ysghim]$ /usr/bin/X11
[ysghim@sanha ysghim]$ /usr/bin/X11
[ysghim@sanha ysghim]$ /usr/bin/X11/
[ysghim@sanha ysghim]$ /usr/bin/X11/
[ysghim@sanha ysghim]$ /usr/bin/X11/x
[ysghim@sanha ysghim]$ /usr/bin/X11/x
[ysghim@sanha ysghim]$ /usr/bin/X11/xt
[ysghim@sanha ysghim]$ /usr/bin/X11/xt
[ysghim@sanha ysghim]$ /usr/bin/X11/xte
[ysghim@sanha ysghim]$ /usr/bin/X11/xte
[ysghim@sanha ysghim]$ /usr/bin/X11/xter
[ysghim@sanha ysghim]$ /usr/bin/X11/xter
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -l
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -l
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -d
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -d
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -di
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -di
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -dis
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -dis
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -disp
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -disp
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -displ
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -displ
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -displa
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -displa
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 1
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 1
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 12
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 12
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.1
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.1
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.16
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.16
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165.
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165.
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165.3
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165.3
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165.37
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165.37
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165.37.
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165.37.
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165.37.2
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165.37.2
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165.37.22
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165.37.22
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165.37.220
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165.37.220
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165.37.220:
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165.37.220:
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165.37.220:0
[ysghim@sanha ysghim]$ /usr/bin/X11/xterm -ls -display 121.165.37.220:0
/usr/X11R6/bin/xterm.real Xt error: Can't open display: 121.165.37.220:0

-------------------------------------------------------
해결방법이 있을까요?

또 갑자기 SSH가 안되는 이유는 무엇일까요?
서버에서 port22 를 막을수도 있나요?...


제품명 : Xmanager 2.x
연결 방법 : Xstart 접속

안녕하세요. 넷사랑컴퓨터 기술지원입니다.

보내주신 원격 실행 결과 창의 내용을 보면, 리눅스 장비에서 PC 쪽으로 TCP 6000~6010번 통신이 가능하지 않아서 발생하는 문제로 보입니다. 리눅스에서 PC 까지 연결된 네트워크 사이에 방화벽이나 공유기 등으로 인해 TCP 통신이 막혀있을 수 있으므로 그 부분을 살펴보시기 바랍니다.

SSH 접속을 이용할 경우에는 PC와 리눅스 장비 사이에 암호화된 터널을 생성하기 때문에, Telnet의 경우와 같이 리눅스 장비에서 PC 쪽으로 TCP 통신에 신경쓸 필요가 없기 때문에 SSH 접속을 추천해 드립니다. SSH 접속이 잘 되다가 갑자기 안된다면 리눅스 장비의 SSH 서비스에 문제가 생겼거나, PC에서 리눅스 장비 쪽으로 TCP 22번 포트 통신이 막혀있을 가능성이 높습니다. 리눅스 장비 담당자에게 문의하셔서 확인해보시기 바랍니다.

감사합니다.