[solved] Unable to resolve any hostnames, including localhost
Hi,
I've been building a custom Linux system for my old 486 laptop, based on a 2.4.31 kernel. At one point networking was working perfectly, but I changed something and now my laptop cannot resolve any hostnames to ip's, including localhost. To simply the problem, please note that this occurs without any modules loaded or pcmcia service running (so I'm not concerned with getting online right now, just being able to resolve localhost into 127.0.0.1 will be enough, because I'm convinced my other networking problems will go away as a result). I've spent a few hours on irc.freenode.net #linux being helped by some very nice people, with no luck. Linux kernel: 2.4.31 Distro: Homemade UMSDOS (original based on latest mulinux, but completely gutted and refitted with new kernel, libraries, and binaries (I just needed a UMSDOS filesystem to get started), with new binaries and libraries copied over from Ubuntu Breezy. My plan is to get it working enough to get online, then use apt-get / dpkg to set up the system properly. /etc/hosts: Code:
127.0.0.1 localhost loopback /etc/host.conf: Code:
order hosts,bind Code:
lo Link encap:Local Loopback Code:
ping: unknown host localhost Code:
PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data. Code:
;; connection timed out; no servers could be reached /bin/hostname mubuntu /sbin/ifconfig lo 127.0.0.1 /sbin/route add -host 127.0.0.1 lo Kernel `make menuconfig' networking configuration: General setup: Code:
[*] Networking support Code:
<M> Packet socket Code:
[*] Network device support Jeff |
There is another file called resolv.conf you did not mention which contains the addresses of the name servers. Perhaps it does not exist or is empty. I think any IP search needs this file and its absence would cause failure.
Eric |
I do have /etc/resolv.conf, but I should note that it is created automatically when I run dhcpcd (so it has nameserver entries related to my isp only). I wasn't aware that it was needed to resolve localhost. What should it contain to resolve localhost to 127.0.0.1?
I have tried with and without the resolv.conf file and it doesn't seem to make a difference. I'm not trying to get online right now (so please don't worry about dhcp or dhcpcd, it's not running.. I don't even have the network card in). Just being able to `ping localhost' and have that work is enough. AFAIK, that shouldn't require dhcp or a network card, since it is the local networking system. Thanks, Jeff |
I don't normally build a machine without a NIC. I wonder if this would have something to do with it. The relationship between localhost and 127.0.0.1 should always be there but if there is no NIC perhaps it is broken. The other necessary files to check are protocols, services, and networks all found in /etc. Perhaps the answer may be found in these? Not sure what else I can think of.
Eric |
Ahh, sorry I don't want to confuse. I can plug in the NIC or not (run dhcpcd, which works, etc), it doesn't seem to make a bit of difference. In fact, with the NIC I can ping internet sites and access them by IP.. but I didn't want to get into the details of the internet configuration. I believe that my online DNS problems have a root cause that is the same that is causing localhost to fail to resolve to 127.0.0.1. If my theory is wrong, that's okay, but it's a separate issue, so I didn't want to confuse the situation, but keep it simple instead.
So, to summarize that: I'd like to be able to access localhost and have it resolve to 127.0.0.1, regardless of whether I can access the rest of the internet by DNS resolution or not. Would you be willing to share the contents of the files you mentioned? I will compare against what I have. Maybe I'm missing something basic, as I put this together myself rather than using packages. Thanks, Jeff |
/etc/protocols from RedHat 6.1:
# /etc/protocols: # $Id: protocols,v 1.1 1995/02/24 01:09:41 imurdock Exp $ # # Internet (IP) protocols # # from: @(#)protocols 5.1 (Berkeley) 4/17/89 # # Updated for NetBSD based on RFC 1340, Assigned Numbers (July 1992). ip 0 IP # internet protocol, pseudo protocol number icmp 1 ICMP # internet control message protocol igmp 2 IGMP # Internet Group Management ggp 3 GGP # gateway-gateway protocol ipencap 4 IP-ENCAP # IP encapsulated in IP (officially ``IP'') st 5 ST # ST datagram mode tcp 6 TCP # transmission control protocol egp 8 EGP # exterior gateway protocol pup 12 PUP # PARC universal packet protocol udp 17 UDP # user datagram protocol hmp 20 HMP # host monitoring protocol xns-idp 22 XNS-IDP # Xerox NS IDP rdp 27 RDP # "reliable datagram" protocol iso-tp4 29 ISO-TP4 # ISO Transport Protocol class 4 xtp 36 XTP # Xpress Tranfer Protocol ddp 37 DDP # Datagram Delivery Protocol idpr-cmtp 39 IDPR-CMTP # IDPR Control Message Transport rspf 73 RSPF #Radio Shortest Path First. vmtp 81 VMTP # Versatile Message Transport ospf 89 OSPFIGP # Open Shortest Path First IGP ipip 94 IPIP # Yet Another IP encapsulation encap 98 ENCAP # Yet Another IP encapsulation /etc/services from RedHat 6.1: # /etc/services: # $Id: services,v 1.4 1997/05/20 19:41:21 tobias Exp $ # # Network services, Internet style # # Note that it is presently the policy of IANA to assign a single well-known # port number for both TCP and UDP; hence, most entries here have two entries # even if the protocol doesn't support UDP operations. # Updated from RFC 1700, ``Assigned Numbers'' (October 1994). Not all ports # are included, only the more common ones. tcpmux 1/tcp # TCP port service multiplexer echo 7/tcp echo 7/udp discard 9/tcp sink null discard 9/udp sink null systat 11/tcp users daytime 13/tcp daytime 13/udp netstat 15/tcp qotd 17/tcp quote msp 18/tcp # message send protocol msp 18/udp # message send protocol chargen 19/tcp ttytst source chargen 19/udp ttytst source ftp-data 20/tcp ftp 21/tcp fsp 21/udp fspd ssh 22/tcp # SSH Remote Login Protocol ssh 22/udp # SSH Remote Login Protocol telnet 23/tcp # 24 - private smtp 25/tcp mail # 26 - unassigned time 37/tcp timserver time 37/udp timserver rlp 39/udp resource # resource location nameserver 42/tcp name # IEN 116 whois 43/tcp nicname re-mail-ck 50/tcp # Remote Mail Checking Protocol re-mail-ck 50/udp # Remote Mail Checking Protocol domain 53/tcp nameserver # name-domain server domain 53/udp nameserver mtp 57/tcp # deprecated bootps 67/tcp # BOOTP server bootps 67/udp bootpc 68/tcp # BOOTP client bootpc 68/udp tftp 69/udp gopher 70/tcp # Internet Gopher gopher 70/udp rje 77/tcp netrjs finger 79/tcp www 80/tcp http # WorldWideWeb HTTP www 80/udp # HyperText Transfer Protocol link 87/tcp ttylink kerberos 88/tcp kerberos5 krb5 # Kerberos v5 kerberos 88/udp kerberos5 krb5 # Kerberos v5 supdup 95/tcp # 100 - reserved hostnames 101/tcp hostname # usually from sri-nic iso-tsap 102/tcp tsap # part of ISODE. csnet-ns 105/tcp cso-ns # also used by CSO name server csnet-ns 105/udp cso-ns # unfortunately the poppassd (Eudora) uses a port which has already # been assigned to a different service. We list the poppassd as an # alias here. This should work for programs asking for this service. # (due to a bug in inetd the 3com-tsmux line is disabled) #3com-tsmux 106/tcp poppassd #3com-tsmux 106/udp poppassd rtelnet 107/tcp # Remote Telnet rtelnet 107/udp pop-2 109/tcp postoffice # POP version 2 pop-2 109/udp pop-3 110/tcp # POP version 3 pop-3 110/udp sunrpc 111/tcp portmapper # RPC 4.0 portmapper TCP sunrpc 111/udp portmapper # RPC 4.0 portmapper UDP auth 113/tcp authentication tap ident sftp 115/tcp uucp-path 117/tcp nntp 119/tcp readnews untp # USENET News Transfer Protocol ntp 123/tcp ntp 123/udp # Network Time Protocol netbios-ns 137/tcp # NETBIOS Name Service netbios-ns 137/udp netbios-dgm 138/tcp # NETBIOS Datagram Service netbios-dgm 138/udp netbios-ssn 139/tcp # NETBIOS session service netbios-ssn 139/udp imap2 143/tcp imap # Interim Mail Access Proto v2 imap2 143/udp imap snmp 161/udp # Simple Net Mgmt Proto snmp-trap 162/udp snmptrap # Traps for SNMP cmip-man 163/tcp # ISO mgmt over IP (CMOT) cmip-man 163/udp cmip-agent 164/tcp cmip-agent 164/udp xdmcp 177/tcp # X Display Mgr. Control Proto xdmcp 177/udp nextstep 178/tcp NeXTStep NextStep # NeXTStep window nextstep 178/udp NeXTStep NextStep # server bgp 179/tcp # Border Gateway Proto. bgp 179/udp prospero 191/tcp # Cliff Neuman's Prospero prospero 191/udp irc 194/tcp # Internet Relay Chat irc 194/udp smux 199/tcp # SNMP Unix Multiplexer smux 199/udp at-rtmp 201/tcp # AppleTalk routing at-rtmp 201/udp at-nbp 202/tcp # AppleTalk name binding at-nbp 202/udp at-echo 204/tcp # AppleTalk echo at-echo 204/udp at-zis 206/tcp # AppleTalk zone information at-zis 206/udp qmtp 209/tcp # The Quick Mail Transfer Protoc ol qmtp 209/udp # The Quick Mail Transfer Protoc ol z3950 210/tcp wais # NISO Z39.50 database z3950 210/udp wais ipx 213/tcp # IPX ipx 213/udp imap3 220/tcp # Interactive Mail Access imap3 220/udp # Protocol v3 rpc2portmap 369/tcp rpc2portmap 369/udp # Coda portmapper codaauth2 370/tcp codaauth2 370/udp # Coda authentication server ulistserv 372/tcp # UNIX Listserv ulistserv 372/udp https 443/tcp # MCom https 443/udp # MCom snpp 444/tcp # Simple Network Paging Protocol snpp 444/udp # Simple Network Paging Protocol saft 487/tcp # Simple Asynchronous File Trans fer saft 487/udp # Simple Asynchronous File Trans fer npmp-local 610/tcp dqs313_qmaster # npmp-local / DQS npmp-local 610/udp dqs313_qmaster # npmp-local / DQS npmp-gui 611/tcp dqs313_execd # npmp-gui / DQS npmp-gui 611/udp dqs313_execd # npmp-gui / DQS hmmp-ind 612/tcp dqs313_intercell# HMMP Indication / DQS hmmp-ind 612/udp dqs313_intercell# HMMP Indication / DQS # # UNIX specific services # exec 512/tcp biff 512/udp comsat login 513/tcp who 513/udp whod shell 514/tcp cmd # no passwords used syslog 514/udp printer 515/tcp spooler # line printer spooler talk 517/udp ntalk 518/udp route 520/udp router routed # RIP timed 525/udp timeserver tempo 526/tcp newdate courier 530/tcp rpc conference 531/tcp chat netnews 532/tcp readnews netwall 533/udp # -for emergency broadcasts uucp 540/tcp uucpd # uucp daemon afpovertcp 548/tcp # AFP over TCP afpovertcp 548/udp # AFP over TCP remotefs 556/tcp rfs_server rfs # Brunhoff remote filesystem klogin 543/tcp # Kerberized `rlogin' (v5) kshell 544/tcp krcmd # Kerberized `rsh' (v5) kerberos-adm 749/tcp # Kerberos `kadmin' (v5) # webster 765/tcp # Network dictionary webster 765/udp # # From ``Assigned Numbers'': # #> The Registered Ports are not controlled by the IANA and on most systems #> can be used by ordinary user processes or programs executed by ordinary #> users. # #> Ports are used in the TCP [45,106] to name the ends of logical #> connections which carry long term conversations. For the purpose of #> providing services to unknown callers, a service contact port is #> defined. This list specifies the port used by the server process as its #> contact port. While the IANA can not control uses of these ports it #> does register or list uses of these ports as a convienence to the #> community. # ingreslock 1524/tcp ingreslock 1524/udp prospero-np 1525/tcp # Prospero non-privileged prospero-np 1525/udp datametrics 1645/tcp old-radius # datametrics / old radius entry datametrics 1645/udp old-radius # datametrics / old radius entry sa-msg-port 1646/tcp old-radacct # sa-msg-port / old radacct entr y sa-msg-port 1646/udp old-radacct # sa-msg-port / old radacct entr y radius 1812/tcp # Radius radius 1812/udp # Radius radacct 1813/tcp # Radius Accounting radacct 1813/udp # Radius Accounting cvspserver 2401/tcp # CVS client/server operations cvspserver 2401/udp # CVS client/server operations venus 2430/tcp # codacon port venus 2430/udp # Venus callback/wbc interface venus-se 2431/tcp # tcp side effects venus-se 2431/udp # udp sftp side effect codasrv 2432/tcp # not used codasrv 2432/udp # server port codasrv-se 2433/tcp # tcp side effects codasrv-se 2433/udp # udp sftp side effect mysql 3306/tcp # MySQL mysql 3306/udp # MySQL rfe 5002/tcp # Radio Free Ethernet rfe 5002/udp # Actually uses UDP only cfengine 5308/tcp # CFengine cfengine 5308/udp # CFengine bbs 7000/tcp # BBS service # # Kerberos (Project Athena/MIT) services # Note that these are for Kerberos v4, and are unofficial. Sites running # v4 should uncomment these and comment out the v5 entries above. # kerberos4 750/udp kerberos-iv kdc # Kerberos (server) udp kerberos4 750/tcp kerberos-iv kdc # Kerberos (server) tcp kerberos_master 751/udp # Kerberos authentication kerberos_master 751/tcp # Kerberos authentication passwd_server 752/udp # Kerberos passwd server krb_prop 754/tcp # Kerberos slave propagation krbupdate 760/tcp kreg # Kerberos registration kpasswd 761/tcp kpwd # Kerberos "passwd" kpop 1109/tcp # Pop with Kerberos knetd 2053/tcp # Kerberos de-multiplexor zephyr-srv 2102/udp # Zephyr server zephyr-clt 2103/udp # Zephyr serv-hm connection zephyr-hm 2104/udp # Zephyr hostmanager eklogin 2105/tcp # Kerberos encrypted rlogin # # Unofficial but necessary (for NetBSD) services # supfilesrv 871/tcp # SUP server supfiledbg 1127/tcp # SUP debugging # # Datagram Delivery Protocol services # rtmp 1/ddp # Routing Table Maintenance Prot ocol nbp 2/ddp # Name Binding Protocol echo 4/ddp # AppleTalk Echo Protocol zip 6/ddp # Zone Information Protocol # # Services added for the Debian GNU/Linux distribution poppassd 106/tcp # Eudora poppassd 106/udp # Eudora mailq 174/tcp # Mailer transport queue for Zma iler ssmtp 465/tcp # SMTP over SSL gdomap 538/tcp # GNUstep distributed objects gdomap 538/udp # GNUstep distributed objects snews 563/tcp # NNTP over SSL ssl-ldap 636/tcp # LDAP over SSL omirr 808/tcp omirrd # online mirror omirr 808/udp omirrd # online mirror rsync 873/tcp # rsync rsync 873/udp # rsync simap 993/tcp # IMAP over SSL spop3 995/tcp # POP-3 over SSL socks 1080/tcp # socks proxy server socks 1080/udp # socks proxy server rmtcfg 1236/tcp # Gracilis Packeten remote confi g server xtel 1313/tcp # french minitel support 1529/tcp # GNATS cfinger 2003/tcp # GNU Finger ninstall 2150/tcp # ninstall service ninstall 2150/udp # ninstall service afbackup 2988/tcp # Afbackup system afbackup 2988/udp # Afbackup system icp 3130/tcp # Internet Cache Protocol (Squid ) icp 3130/udp # Internet Cache Protocol (Squid ) postgres 5432/tcp # POSTGRES postgres 5432/udp # POSTGRES fax 4557/tcp # FAX transmission service (old) hylafax 4559/tcp # HylaFAX client-server protocol (new) noclog 5354/tcp # noclogd with TCP (nocol) noclog 5354/udp # noclogd with UDP (nocol) hostmon 5355/tcp # hostmon uses TCP (nocol) hostmon 5355/udp # hostmon uses TCP (nocol) ircd 6667/tcp # Internet Relay Chat ircd 6667/udp # Internet Relay Chat webcache 8080/tcp # WWW caching service webcache 8080/udp # WWW caching service tproxy 8081/tcp # Transparent Proxy tproxy 8081/udp # Transparent Proxy mandelspawn 9359/udp mandelbrot # network mandelbrot amanda 10080/udp # amanda backup services kamanda 10081/tcp # amanda backup services (Kerber os) kamanda 10081/udp # amanda backup services (Kerber os) amandaidx 10082/tcp # amanda backup services amidxtape 10083/tcp # amanda backup services isdnlog 20011/tcp # isdn logging system isdnlog 20011/udp # isdn logging system vboxd 20012/tcp # voice box system vboxd 20012/udp # voice box system binkp 24554/tcp # Binkley binkp 24554/udp # Binkley asp 27374/tcp # Address Search Protocol asp 27374/udp # Address Search Protocol tfido 60177/tcp # Ifmail tfido 60177/udp # Ifmail fido 60179/tcp # Ifmail fido 60179/udp # Ifmail # Local services linuxconf 98/tcp swat 901/tcp |
Thanks a lot, I'll try that out when I get home :)
|
Check you /etc/nsswitch.conf file. In the line "hosts: " make sure "files" is listed. Here is mine:
Quote:
|
did u check whether icmp is block on your system there is a file in proc/networking...ipv4
and there is file something like icmp dont remember the name. |
EricEarl and bluej: I added the mentioned files to /etc, rebooted, no change.
Quote:
ls -R /proc/net Code:
/proc/net: Code:
IP address HW type Flags HW address Mask Device |
Solved it! I was missing the /lib/libnss* libraries. All works well now. Discovered this from reading the busybox Login/Password use internal functions Help option. I wouldn't have recognized it for what it was unless /etc/nsswitch.conf was mentioned.. so thanks bluej :D.
Thanks a lot for everyone's help, Jeff |
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