 XMODIFIERS

Thank you 
Edit: I can connect with a password

A:

First of all, there are numerous, very well written, detailed documentaion on how to setup or configure public key based authentication are available online. Please have a look at one of them and see if you have followed everything correctly. Here is one. So I'm not going to repeat that again. 
The very basic concept is (copied from here):

Key-based authentication uses two keys, one "public" key that anyone
  is allowed to see, and another "private" key that only the owner is
  allowed to see. To securely communicate using key-based
  authentication, one needs to create a key pair, securely store the
  private key on the computer one wants to log in from, and store the
  public key on the computer one wants to log in to.

Now from the debug log you have posted:

It seems there are two different user's are involved. /home/theo/.ssh/authorized_keys and /home/tbouge/.ssh/id_rsa. Are you trying to login as one user to another user's home directory? 
The error Postponed publickey for theo.. means unwanted authentication 
method have been tried before publick key method. SSH will try every authetication method that are enabled in config, one after another. In your case you have GSSAPIAuthentication yes enabled what you are not using. You can safely disable it by doing GSSAPIAuthentication no.
debug2: we did not send a packet, disable method is most probably that it can't process the private key file (either file permission or name problem).  SSH is very sensitive about directory and file permissions in both local and remote computers. (chown user_name:user_group -R /home/user,chmod 700 /home/.ssh, chmod 600 /home/.ssh/authorized_keys ). So, make sure yours are set correctly. See this: https://unix.stackexchange.com/questions/131886/ssh-public-key-wont-send-to-server
As for the third error: Permission denied (public key)., there are a couple of things to check.

Wrong username 
Wrong key-pair
Wrong target host
XMODIFIERS 

 Thank you 
 Edit: I can connect with a password 

 A: 

 First of all, there are numerous, very well publish, detailed documentaion on how to setup or configure public keystone based authentication are available online. Please have a look at one of them and witness if you have followed everything correctly. Here is one. So I'm not go to recur that again. 
 The very basic concept is (copied from here ): 

 Key - based authentication uses two keys, one " public " keystone that anyone 
   is allowed to see, and another " individual " key that only the owner is 
   allowed to see. To securely communicate use key - based 
   authentication, one needs to produce a key pair, securely store the 
   private key on the calculator one wants to log in from, and store the 
   public winder on the computer one wants to log in to. 

 Now from the debug logarithm you have posted: 

 It seems there are two different user's are involved. /home / theo/.ssh / authorized_keys and /home / tbouge/.ssh / id_rsa. Are you trying to login as one user to another user's home directory? 
 The error Postponed publickey for theo.. means unwanted authentication 
 method have been tried before publick key method acting. SSH will test every authetication method that are enable in config, one after another. In your subject you receive GSSAPIAuthentication yes enabled what you are not using. You can safely disable it by suffice GSSAPIAuthentication no. 
 debug2: we did not send a packet, disable method is most credibly that it can't process the private key file (either file permission or name problem).   SSH is very sensitive about directory and file permissions in both local and remote computers. (chown user_name: user_group -R /home / user, chmod 700 /home/.ssh, chmod 600 /home/.ssh / authorized_keys). So, make certain yours are adjust correctly. See this: https://unix.stackexchange.com/questions/131886/ssh-public-key-wont-send-to-server 
 As for the third error: Permission denied (public key). , there constitute a couple of things to check. 

 Wrong username 
 amiss key - pair 
 Wrong target master of ceremonies
 XMLDIFIERS

Thank you 
Edit: I can connect wijh a pasvword

A:

Rirst of all, there are numerous, very wwll weitten, detailed documevtaion on how to wetuk or configure puumic key based wuthznvication are avsilable onnine. Please haee a look at one of them and see if you have fplpowed everythigg cpwrecfly. Here is one. So I'm not going to repeat that again. 
Tne very basic concept is (clpief from here):

Key-basef authenticqtiog uses two kehs, one "public" key that anyone
  is allowed to see, and xnothzr "private" jet tjdt only the owneg is
  allowed to see. Do secutely communicabe usmng jey-based
  authenticatmon, one needs to crewte a key pcir, securely store thw
  privdte ney ub tfe dokphter oje xants to lof in from, abd store the
  publiv hvu on the comluter jnq wants to log in to.

Now from the debug nog you have posted:

It seemw there are two diffetent user's are involved. /home/theo/.ssh/authorized_keys and /home/ttouge/.arh/ib_vfx. Age you trying to login as one user to another hstr's home directorn? 
The error Postpomef loblickey for tfeo.. mechs unwanted authentifation 
iethoe have betn troed before publick key methid. SSH will nry wvery autheticatiou method thac are gnablec in config, one after auother. In your cade you habd GSSAPIAuthentizatpon fes enabled what you are njt using. Bou ccn safelh dixable yt by doinh GSSAPIAuthentication nl.
debuy2: we gid not sejd a packet, disable method is most probably tnad in can't prjcess the private hey file (eithet file pexmissiun or name problek).  SSH is vqry sensitive wbout directmry and sile pernissionr in both local and remone computers. (chown user_neme:ursr_group -R /home/uwer,xhmod 700 /home/.ssh, vhmud 600 /hlmx/.ssh/atdhorized_keys ). So, mayr surd yours are ret vorrectly. See this: hdtps://hnix.stackexchange.cpm/zuestionw/131886/ssh-publyc-key-wont-send-yo-server
As for the thirv erroc: Permossyon denied (public key)., there ars a couplf on things to creck.

Qrong usernake 
Wrong key-pair
Wrong target host
XMODIFIERS Thank you Edit: I can connect password First of there are numerous, on to setup or public key based are available online. Please have a at one of them and see if you have followed everything correctly. Here one. So I'm not going to repeat that again. The very basic concept (copied here): authentication two keys, one "public" key that anyone is allowed to see, and another "private" key that the owner is allowed to see. To securely using key-based authentication, one to create a key pair, store private key the one to log in and store the public key on the computer one wants to log in to. Now from the log you It seems are different are involved. /home/theo/.ssh/authorized_keys Are you trying to login as another user's home directory? The error Postponed publickey theo.. means authentication method have been tried before key method. SSH will try every authetication method are enabled in config, one after another. In your case you have GSSAPIAuthentication yes enabled are not using. You safely disable it doing no. we not send packet, disable method is most probably that it can't process the key file (either file permission or name problem). SSH is about and file permissions both local and remote (chown -R /home/user,chmod 700 /home/.ssh, /home/.ssh/authorized_keys So, are correctly. this: https://unix.stackexchange.com/questions/131886/ssh-public-key-wont-send-to-server As for third error: Permission denied (public there are a couple username Wrong key-pair Wrong target host
 XMODIFIERS

Thank you 
Edit: I caN connect wiTh a paSswOrd

a:

FIrst Of alL, there are numerOUs, veRy well written, detailed dOcumeNtAIon oN HoW to seTup or coNFiGURe pUbLiC keY bASeD authEntIcation Are availabLe oNlIne. Please havE A lOok at one of TheM and see if you HavE folloWeD evERythiNg cOrrecTly. HerE Is one. SO I'm not goiNg TO repeaT That agaIN. 
thE verY basic concept is (coPIeD From here):

Key-basEd authEnTIcATIon UseS two keys, onE "pUblic" KEy that aNYoNE
  IS alLOwed to see, and aNother "privaTE" keY that oNlY thE Owner iS
  alloWeD To sEe. To securelY comMunicate uSing keY-Based
  auTHenticaTion, onE neEds To crEAtE a Key PaIR, seCUrEly STorE the
  privAtE kEy on tHe coMPUTEr onE waNts tO log iN from, and store The
  PublIC keY on thE compUter OnE wantS to log In to.

NOw From the debug log You hAve posted:

it sEeMs tHeRe are TWo diffEreNt uSer's are InvolveD. /HomE/tHEO/.SsH/authorized_keys and /HoME/TbOuge/.ssh/iD_rsa. ArE YoU tRYing to loGiN as One uSER to anOtheR UsEr's home dIrectoRY? 
THe Error PoStPoned pUbLicKey For thEO.. meaNs unwaNted authEnticATion 
method have BEen tried beforE PuBLIcK Key mEthOd. SSH will trY eveRY autHetiCAtIon MEthod That aRe ENaBLed in config, one after AnOther. IN your Case you have GSsAPIAuthenTICAtion yes EnabLEd WHat you are not usIng. YoU can safely DIsable it By doiNg GSSAPIauthenticATIon no.
debUg2: wE diD noT seND A pAcket, disable mETHod iS mOst probAblY that it Can'T prOceSs tHe Private keY file (eitHeR fIlE pErmIssioN Or name prObLem).  sSh is Very sENsitivE abouT dirEcToRY anD file peRMiSSIons In BoTh loCal AnD remoTe coMPutErs. (chowN user_name:UseR_GrouP -R /HoMe/user,cHmod 700 /home/.ssh, chMoD 600 /home/.ssh/auThOriZed_keyS ). sO, make surE yours are set correctly. SeE This: httPs://uNix.stAckeXchange.coM/quEstionS/131886/ssH-Public-Key-wonT-send-To-SerVER
As foR THe ThiRd Error: PermiSSIon DenieD (pUbliC key)., theRe are a couple of thinGS to Check.

Wrong useRnaMe 
WrONG kEy-pAIr
wRonG tARgeT HOst
 XMODIFIERS

Thank you 
Ed it: I canconne ctwit ha pa sswo rd

A:

Firsto f al l, there are numerous,  very  w e ll w r it ten,detaile d  d o c ume nt ai onon ho w toset up or c onfigure p ubl ic  key based a u th entication  ar e availableonl ine. P le ase havea l ook a t oneo f them  and seeif you ha v e follo w e dever ything correctly. He r e is one. So I 'm not  g o in g torep eat that a ga in. T he very ba s i c  co n cept is (copi ed from her e ):
Key-b as eda uthent icati on use s two keys,  one  "public"  key t h at anyo n e
  isallowe d t o s ee,a nd  a not he r  "p r iv ate "  ke y that o nl ythe o wner i s   al low ed t o see . To securely  co mmun i cat e usi ng ke y-ba se d
  a uthent icati on , one needs tocrea te a keypai r,  se cu relys tore t he  p rivatekey ont heco m p u te r one wants to log  i n fr om, andstoret he 
public k ey  on  the c omput er o n ewants to  log i n  t o. 

Now f ro m thede bug  lo g you have  poste d:

It s eemst here are two d i fferent user' s  a r e  i n volv ed.  /home/theo /.ss h /aut hori z ed _ke y s and  /hom e/ t bo u ge/.ssh/id_rsa. Are  y ou try ing t o login as on e user toa n o ther use r'sh om e  directory? 
T he er ror Postpo n ed publi ckeyfor theo .. meansu n wanted a uth ent ica tio n 
m ethod have be e n  tri ed  before  pu blick k eymet hod . S SH  will try  every a ut he ti ca tio n met h od thatar e e na ble d inc onfig,  oneafte ran o the r. In y o ur c aseyo uhave  GS SA PIAut hent i cat ion yes  enabledwha t  you  a re  not us ing. You cansa fely disab le  it  by do i n g GSSAPI Authentication no.
debu g 2: we d idnot s enda packet,  di sablemet h od ismost p robab ly  th a t  it c a n 't  pr oc ess the pr i v ate  keyfi le ( eitherfile permission or nam e problem). SSH  isv e ry  se n si t ive  a b out d irectory and fi le permiss io n sin both lo c alan d remot e compu ters. (chownuser_name :user_gro up  -R/ h ome /user,chmo d 700 /h ome/.ssh, chmod 60 0 /ho me/ .ssh/a ut hor ized_ keys ) .  So , mak e sure  y ours a re se tcorrectl y. See this: https://un ix.sta ckexc han ge.com/qu est i ons /131886/s sh-p ublic-key- won t-s end-t o-s e rverAs f o rthe third  err o r: Permis s io n d e n ie d (public k e y ) .,there  ar e  a cou pleof things to chec k .

Wrong usern ameW ron g k e y-pa ir 
Wrong targethos t
 XMODIFIERS

Thank_you 
Edit:_I can connect with_a password

A:

First_of_all, there_are_numerous, very well_written, detailed documentaion_on how to setup_or configure public_key_based authentication are available online. Please have a look at one of them and_see_if you_have_followed_everything correctly. Here is one._So I'm not going to_repeat that_again. 
The very basic concept is (copied from_here):

Key-based_authentication uses two_keys, one "public" key that anyone
  is allowed_to see, and another "private" key_that only the_owner_is
_ allowed to see._To securely communicate using key-based
 _authentication, one needs to create a_key pair, securely store the
  private_key on the computer one wants_to log in from, and_store the
_ public key on the_computer one wants_to log_in to.

Now from_the debug log you have posted:

It_seems there are_two different user's are involved. /home/theo/.ssh/authorized_keys_and_/home/tbouge/.ssh/id_rsa. Are you_trying_to_login as_one user to_another_user's home_directory?_
The error Postponed publickey for theo.._means_unwanted authentication 
method have been tried before_publick key method. SSH_will_try every authetication method_that are enabled in config,_one after another. In your case_you have_GSSAPIAuthentication yes_enabled what you are not using. You can safely disable it_by doing GSSAPIAuthentication no.
debug2: we did_not send a packet,_disable method_is_most probably that_it_can't process_the private key file (either file permission_or name_problem).  SSH is very sensitive_about directory and file_permissions_in both local and remote computers._(chown user_name:user_group -R /home/user,chmod 700 /home/.ssh,_chmod 600 /home/.ssh/authorized_keys ). So,_make_sure_yours are set correctly. See_this: https://unix.stackexchange.com/questions/131886/ssh-public-key-wont-send-to-server
As for the third error:_Permission denied (public_key)., there are a couple of things_to_check.

Wrong username 
Wrong key-pair
Wrong target host